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In the recently discovered proton-coupled energy transfer (PCEnT) mechanism, the transfer of electronic excitation energy between donor and acceptor chromophores is coupled to a proton transfer reaction. Herein, we develop a general theory for PCEnT and derive an analytical expression for the nonadiabatic PCEnT rate constant. This theory treats the transferring hydrogen nucleus quantum mechanically and describes the PCEnT process in terms of nonadiabatic transitions between reactant and product electron–proton vibronic states. The rate constant is expressed as a summation over these vibronic states, and the contribution of each pair of vibronic states depends on the square of the vibronic coupling as well as the spectral convolution integral, which can be viewed as a generalization of the Förster-type spectral overlap integral for vibronic rather than electronic states. The convolution integral also accounts for the common vibrational modes shared by the donor and acceptor chromophores for intramolecular PCEnT. We apply this theory to model systems to investigate the key features of PCEnT processes. The excited vibronic states can contribute significantly to the total PCEnT rate constant, and the common modes can either slow down or speed up the process. Because the pairs of vibronic states that contribute the most to the PCEnT rate constant may correspond to spectroscopically dark states, PCEnT could occur even when there is no apparent overlap between the donor emission and acceptor absorption spectra. This theory will assist in the interpretation of experimental data and will guide the design of additional PCEnT systems. [ABSTRACT FROM AUTHOR]

In this paper, mole fraction dependent strain in a III-nitride alloy and its effects on built-in polarization and quantized states in multi-quantum-wells (MQWs) have been investigated. The internal electric field arising out of spontaneous and piezoelectric polarizations in the presence of strain has been calculated. Then, the energy eigenvalues and wavefunctions of carriers in the modified potential well configurations have been computed by solving a time-independent Schrödinger equation using a finite difference method. Next, the overlap integrals between the wavefunctions of bound states in conduction and valence bands, an important consideration for optical transitions, have been computed and plotted. The results are shown taking three nitride-based MQW structures InGaN/GaN, GaN/AlGaN, and InGaN/InAlN as examples. The study helps choose suitable mole fractions for the improved and desired performance of the nitride MQW based devices. [ABSTRACT FROM AUTHOR]

A polycrystalline sample LuCrO3 has been characterized by neutron powder diffraction (NPD) and magnetization measurements. Its crystal structure has been Rietveld refined from NPD data in space group Pnma; this perovskite contains strongly tilted CrO6 octahedra with extremely bent Cr—O—Cr superexchange angles of ∼142°. The NPD data show that below Néel temperature (TN≃131 K), the magnetic structure can be defined as an A‐type antiferromagnetic arrangement of Cr3+ magnetic moments, aligned along the b axis, with a canting along the c axis. A noticeable magnetostrictive effect is observed in the unit‐cell parameters and volume upon cooling down across TN. The AC magnetic susceptibility indicates the onset of magnetic ordering below 112.6 K; the magnetization isotherms below TN show a nonlinear behaviour that is associated with the described canting of the Cr3+ magnetic moments. From the Curie–Weiss law, the effective moment of the Cr3+ sublattice is found to be μeff = 3.55 μB (calculated 3.7 μB) while the ΘCW parameter yields a value of −155 K, indicating antiferromagnetic interactions. There is a conspicuous increase of TN upon the application of external pressure, which must be due to shortening of the Cr—O bond length under compression that increases the orbital overlap integral. [ABSTRACT FROM AUTHOR]

With the exponential growth in information related applications and the continuous increase in voice over IP (VoIP) applications, the carriers are expanding their networks to provide improved services to their end users. In such cases, the synchronous optical network/synchronous digital hierarchy model is not suitable. In this work, we are going to investigate the electro optic switch with the help of a VB script to simulate the device for various parameters. Further, we will then scan the central electrode voltages and take account of the overlap integral taking place at the output port with the help of waveguide mode. The best switching for switches at different voltages so as to have negligible coupling loss for different input signals is investigated. We aim to evaluate the MZI switches with the Li-Tn channel profile wave guiding structure and confirm their performance as compared to the existing MZI switches. [ABSTRACT FROM AUTHOR]

In this work, the propagation of OAM modes in multimode interference (MMI) waveguides, as the basic elements in many integrated optical devices, is studied to utilize their benefits in integrated OAM applications. OAM modes shape the OAM-maintaining image at the specific length of an MMI waveguide. As the most effective parameters on the properties of the generated image, waveguide's width (W), topological charge (ℓ ) and waist radius (WR) of the input OAM modes are investigated. Power overlap integral (POI) is used to evaluate the quality of images. The investigations show that the calculated POI is enhanced by increasing in WR of the input mode (from 86.91% for WR = 1.5 µm to 98.92% for WR = 3.5 µm; where W = 15 µm and ℓ = ± 1 ). Furthermore, the increase in the waveguide's width leads to decrease the quality of the self-imaged mode (from 98.90% for W = 15 µm to 85.15% for W = 50 µm; where WR = 3 µm and ℓ = ± 1 ). It is also demonstrated that mode conversion between even order of OAM modes with opposite topological charges can occur at OAM-maintaining length of the MMI waveguides, which is the most outstanding achievement of this survey for optical communication systems. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the luminescence and kinetic properties of 1.1-nm-thick colloidal CdSe nanoplatelets rolled up into scrolls in an external electric field in the range of 0–150kV/cm. Luminescence spectroscopy revealed that placing CdSe nanoscrolls in an external electric field leads to quenching of the intensity of luminescence bands with an increasing electric field, whereas time-correlated single photon counting measurements demonstrate the acceleration of the relaxation processes of electronic excitation. These effects are due to a reduction in the overlap integral between the electron and hole wavefunctions which is the reason for the emergent field-induced luminescence quenching. [ABSTRACT FROM AUTHOR]

A detailed spectroscopic study (fluorescence, absorption, and lifetime) was conducted to gain insight into the nature of the binding interaction between fluorophore Hoechst33258 (H258) and jaundice marker Bilirubin (Br). The fluorescence emission of the H258 (Ex/Em = 340-502nm) showed a conc. dependent quenching in the presence of Br (1.25 μ M to 10 μ M). The Stern-Volmer constant demonstrated an upward curve depicting the occurrence of both static and dynamic quenching with an acquired value of K SV = 3.1x 10 3 M - 1 and biomolecular quenching rate constant K q = 8.6 x 10 11 M - 1 S - 1 . The static quenching was evaluated using the sphere of action model and a sphere radius of 0.3nm indicated the presence of a static component in the quenching. The FRET analysis with overlap integral (J) = 1.4x10 14 M - 1 cm - 1 nm 4 and Foster Radius(R 0 ) = 26.82 Å with 59% efficiency suggested occurrence of dynamic quenching. Further studies with the time-resolved fluorescence also indicated the presence of dynamic quenching. The lifetime values of H258 reduced from 3.9ns to 0.5ns. Molecular docking studies further support both static and dynamic components in quenching. A non-covalent interaction of H258 with Br in the presence of HSA is predominantly characterized by H-bonding with residues Lys, Asn, Glu, Gln, and Br. The H258 and Br interaction was within the distance of 3.04 Å, which is in coherence with the sphere of action model (0.3nm) and Van-der-Waals along with hydrophobic interactions, which suggested both static and dynamic quenching. Thus, H258 can serve as an efficient fluorophore to monitor binding interactions and can be further exploited as a suitable probe for investigating conformational changes and detection of Br in subsequent studies. [ABSTRACT FROM AUTHOR]

Second-order N-electron valence state perturbation theory (NEVPT2) is an exactly size-consistent and intruder-state-free multi-reference theory. To accelerate the NEVPT2 computation, Guo and Neese combined it with the local pair-natural orbital (PNO) method using the projected atomic orbitals (PAOs) as the underlying local basis [Guo et al., J. Chem. Phys. 144, 094111 (2016)]. In this paper, we report the further development of the PNO-NEVPT2 method using the orthonormal and non-redundant localized virtual molecular orbitals (LVMOs) instead of PAOs. The LVMOs were previously considered to perform relatively poor compared to PAOs because the resulting orbital domains were unacceptably large. Our prior work, however, showed that this drawback can be remedied by re-forming the domain construction scheme using differential overlap integrals [Saitow et al., J. Chem. Phys. 157, 084101 (2022)]. In this work, we develop further refinements to enhance the feasibility of using LVMOs. We first developed a two-level semi-local approach for screening out so-called weak-pairs to select or truncate the pairs for PNO constructions more flexibly. As a refinement specific to the Pipek–Mezey localization for LVMOs, we introduced an iterative scheme to truncate the Givens rotations using varying thresholds. We assessed the LVMO-based PNO-NEVPT2 method through benchmark calculations for linear phenyl alkanes, which demonstrate that it performs comparably well relative to the PAO-based approach. In addition, we evaluated the Co–C bond dissociation energies for the cobalamin derivatives composed of 200 or more atoms, which confirms that the LVMO-based method can recover more than 99.85% of the canonical NEVPT2 correlation energy. [ABSTRACT FROM AUTHOR]

We show that the first-order logical theory of the binary overlap-free words (and, more generally, the $\alpha $ -free words for rational $\alpha $ , $2), is decidable. As a consequence, many results previously obtained about this class through tedious case-based proofs can now be proved "automatically," using a decision procedure, and new claims can be proved or disproved simply by restating them as logical formulas. [ABSTRACT FROM AUTHOR]

Molecular chirality has long been monitored in the frequency domain in the ultraviolet, visible, and infrared regimes. Recently developed time-domain approaches can detect time-dependent chiral dynamics by enhancing intrinsically weak chiral signals. Evenorder nonlinear signals in chiral molecules have gained attention thanks to their existence in the electric dipole approximation, without relying on the weaker higherorder multipole interactions. We illustrate the optimization of temporal polarization pulse-shaping in various frequency ranges (infrared/optical and optical/X ray) to enhance chiral nonlinear signals. These signals can be recast as an overlap integral of matter and field pseudoscalars which contain the relevant chiral information. Simulations are carried out for second- and fourth-order nonlinear spectroscopies in L-tryptophan. [ABSTRACT FROM AUTHOR]

We implemented a screening algorithm for one-electron-three-center overlap integrals over contracted Gaussian-type orbitals into the Q-Chem program package. The respective bounds were derived using shell-bounding Gaussians and the Obara–Saika recurrence relations. Using integral screening, we reduced the computational scaling of the Gaussians On Surface Tesserae Simulate HYdrostatic Pressure (GOSTSHYP) model in terms of calculation time and memory usage to a linear relationship with the tesserae used to discretize the surface area. Further code improvements allowed for additional performance boosts. To demonstrate the algorithm's better performance, we calculated the compressibility of fullerenes up to C180, where we were originally limited to C40 due to the high RAM usage of GOSTSHYP. [ABSTRACT FROM AUTHOR]

Three- and four-center Coulomb integrals in the solid spherical harmonic Gaussian basis are solved by expansion in terms of two-center integrals. The two-electron Gaussian product rule, coupled with the addition theorem for solid spherical harmonics, reduces four-center Coulomb integrals into a linear combination of two-center Coulomb integrals and one-center overlap integrals. With this approach, three- and four-center Coulomb integrals can be reduced to the same form of two-center integrals. Resulting two-center Coulomb integrals can be further simplified into a simpler form, which can be related to the Boys function. Multi-center Coulomb integrals are solved hierarchically: simple two-center Coulomb integrals are used for calculation of more complicated two-center Coulomb integrals, which are used in the calculation of multicenter integrals. [ABSTRACT FROM AUTHOR]

The interaction mechanism between xanthan gum (XG) and bovine serum albumin (BSA) was studied by various spectral and molecular docking techniques. The fluorescence spectrum analysis reveals that XG and BSA are quenched, with XG quenching BSA in a static manner according to the Stern-Volmer equation. The Vant's Hoff equation indicates negative values for the thermodynamic parameters ΔH, ΔG, and ΔS during the binding process. Therefore, it can be concluded that hydrogen bonding and van der Waals forces dominate the interaction between XG and BSA, resulting in a spontaneous and exothermic quenching process. The results of molecular docking simulation show that hydrogen bond and van der Waals force are the main forces between XG and BSA. Through multispectral analysis, it is observed that XG affects the microenvironment of BSA by increasing its polarity and hydrophilicity while weakening its hydrophobicity. This leads to changes in the secondary structure of BSA molecules. The binding distance between XG and BSA is calculated to demonstrate energy transfer between them, and overlap integral calculations confirm the presence of non-radiative energy transfer from XG to BSA. Analysis of the circular dichroism spectrum reveals that interaction between BSA and XG leads to protein relaxation, a decrease in α-helix structure, and an increase in β-sheet structure, providing further evidence for alterations in the secondary structure of BSA. Through the study of the interaction between XG and BSA, the interaction mechanism of both is analyzed, which provides data support for their future discussion and research. [ABSTRACT FROM AUTHOR]

Herein, we report on a fluorine-doped single-walled carbon nanotube (FSWCNT) phenomenon, that yields tunable high-frequency self-sustained acoustoelectric direct current (ADC) oscillations. A tractable analytical method was used in the hypersound domain, to base the calculations on carriers in the lowest miniband. Hypothetically, the energy of interaction between the carriers and the acoustic phonons is less than the energy of the typical carriers. High-order harmonics of the acoustic phonons' effective field could be disregarded under this supposition. The ADC was observed to exhibit a nonlinearity, that resulted from the carrier distribution function's distortion as a result of interaction with the acoustic phonons, which had strong nonlinear effects. Theoretically, we demonstrated that the dynamics of space charge instabilities, due to Bragg reflection of Bloch oscillating carriers in the FSWCNT's miniband, were the only factors which contributed to the creation of radiation in the terahertz (THz) frequency range. The study also investigated the influence of various FSWCNT parameters such as the overlapping integrals ( Δ s and Δ z ), ac-field E 1 , and carrier concentration n o on the behaviour of the ADC. The results showed that the intensity of the ADC oscillation J z z a e / J o a e could be tuned by adjusting Δ s , Δ z , E 1 , and n o .This tunability suggests that FSWCNTs could be used as an active device operating at very high frequencies, potentially reaching the submillimeter wavelength range. The study also suggests the possibility of domain suppression and acoustic Bloch gain through dynamic ADC stabilisation. [ABSTRACT FROM AUTHOR]

Revealing the energy transfer (ET) process from excitons to rare earth ions in halide perovskites has great guiding value for designing optoelectronic materials. Here, the multiple ET channels in multi‐exciton emissive Sb3+/Nd3+ co‐doped Cs2ZrCl6 are explored to comprehend the ET processes. Förster–Dexter ET theory reveals that the sensitizer concentration rather than the overlap integral of the spectra plays the leading function in the comparison of the ET efficiency among multiple ET channels from the host self‐trapped excitons (STEs) and dopant triplet STEs to Nd3+ ions. Besides, Sb3+/Nd3+ co‐doped Cs2ZrCl6 enables varied color delivery and has great potential as anti‐counterfeiting material. Under X‐ray irradiation, Sb3+/Nd3+ co‐doped Cs2ZrCl6 presents a high light yield of ≈13300 photons MeV−1 and promising X‐ray imaging ability. This work provides new insight for investigating the ET efficiency among multiple ET processes and presents great potentiality of multi‐exciton emissive perovskites in the fields of anti‐counterfeiting and X‐ray imaging. [ABSTRACT FROM AUTHOR]

This paper proposes a frequency-time hybrid solver for the time-dependent wave equation in two-dimensional interior spatial domains. The approach relies on four main elements, namely, (1) A multiple scattering strategy that decomposes a given interior time-domain problem into a sequence of limited-duration time-domain problems of scattering by overlapping open arcs, each one of which is reduced (by means of the Fourier transform) to a sequence of Helmholtz frequency-domain problems ; (2) Boundary integral equations on overlapping boundary patches for the solution of the frequency-domain problems in point (1); (3) A smooth "Time-windowing and recentering" methodology that enables both treatment of incident signals of long duration and long time simulation; and, (4) A Fourier transform algorithm that delivers numerically dispersionless, spectrally-accurate time evolution for given incident fields. By recasting the interior time-domain problem in terms of a sequence of open-arc multiple scattering events, the proposed approach regularizes the full interior frequency domain problem—which, if obtained by either Fourier or Laplace transformation of the corresponding interior time-domain problem, must encapsulate infinitely many scattering events, giving rise to non-uniqueness and eigenfunctions in the Fourier case, and ill conditioning in the Laplace case. Numerical examples are included which demonstrate the accuracy and efficiency of the proposed methodology. [ABSTRACT FROM AUTHOR]

The multireference second-order perturbation theory (CASPT2) is known to deliver a quantitative description of various complex electronic states. Despite its near-size-consistent nature, the applicability of the CASPT2 method to large, real-life systems is mostly hindered by large computational and storage costs for the two-external tensors, such as two-electron integrals, amplitudes, and residuum. To this end, Menezes and co-workers developed a reduced-scaling CASPT2 scheme by incorporating the local pair-natural orbital (PNO) representation of the many-body wave functions using non-orthonormal projected atomic orbitals (PAOs) into the CASPT theory [F. Menezes et al., J. Chem. Phys. 145, 124115 (2016)]. Alternatively, in this paper, we develop a new PNO-based CASPT2 scheme using the orthonormal localized virtual molecular orbitals (LVMOs) and assess its performance and accuracy in comparison with the conventional PAO-based counterpart. Albeit the compactness, the LVMOs were considered to perform somewhat poorly compared to PAOs in the local correlation framework because they caused enormously large orbital domains. In this work, we show that the size of LVMO domains can be rendered comparable to or even smaller than that of PAOs by the use of the differential overlap integrals for domain construction. Optimality of the MOs from the CASSCF treatment is a key to reducing the LVMO domain size for the multireference case. Due to the augmented Hessian-based localization algorithm, an additional computational cost for obtaining the LVMOs is relatively minor. We demonstrate that the LVMO-based PNO-CASPT2 method is routinely applicable to large, real-life molecules such as Menshutkin SN2 reaction in a single-walled carbon nanotube reaction field. [ABSTRACT FROM AUTHOR]

Transient absorption (TA) and time-resolved photoluminescence (PL) spectroscopies have been used to elucidate the hole tunneling and Auger dynamics in biexcitons and negative trions in high-quality InP/ZnSe/ZnS quantum dots (QDs). In a previous paper [Nguyen et al., J. Phys. Chem. C 125, 15405–15414 (2021)], we showed that under high-intensity photoexcitation, two types of biexcitons are formed: those having two conduction band electrons and two valence band holes (designated as an XX state) and those having two conduction band electrons, one valence band hole, and an additional trapped hole (designated as an XT state). In the present paper, we show that both types of biexcitons can undergo Auger processes, with those of the XT state being a factor of four to five slower than those of the XX state. In addition, the trapped holes can undergo tunneling into the valence band, converting an XT state to an XX state. The relative amplitudes of the fast (XX) and slow (XT) components are different in the TA and PL kinetics, and these differences can be quantitatively understood in terms of oscillator strengths and electron–hole overlap integrals of each state. XT to XX hole tunneling rates are obtained from the comparison of the XT state lifetimes with those of the negative trions. This comparison shows that the tunneling times decrease with decreasing core size and shell thickness. These times are about 2 ns for the thinnest shell red-emitting QDs and decrease to 330 ps for QDs that luminesce in the yellow. [ABSTRACT FROM AUTHOR]

The detection of radially excited charmonium and charm meson states, and measurement of heavy meson decays, particularly B c + → J / ψ D s + and B c + → J / ψ D s ∗ + , by the LHCb and ATLAS Collaborations, have aroused a lot of theoretical interest in the nonleptonic decays of b-flavored mesons. In this paper, we study the exclusive two-body nonleptonic B ¯ 0 , B s 0 ¯ , B - and B c - -meson decays to two vector meson ( V 1 (n S) V 2 ) states. Assuming the factorization hypothesis, we calculate the weak-decay form factors from the overlapping integrals of meson wave functions, in the framework of the relativistic independent quark (RIQ) model. We find a few dominant decay modes: B - → D ∗ 0 ρ - , B 0 ¯ → D ∗ + ρ - , B s 0 ¯ → D s ∗ + ρ - , B - → J / ψ K ∗ - and B c - → J / ψ D s ∗ - with predicted branching fractions of 1.52, 1.40, 1.16, 0.46 and 0.27 (in % ), which are experimentally accessible. The predicted branching fractions for corresponding decay modes to excited (2S) states, obtained in O (10 - 3 - 10 - 4) lie within the detection accuracy of the current experiments at LHCb and Tevatron. Our predicted CP-odd fractions ( R ⊥ ) for color-favored B c -decays to two charmful states ( D ∗ D (s) ∗ ) are found significant as compared to similar decay modes of other b-flavored mesons. [ABSTRACT FROM AUTHOR]

Coupled optical cavities are an attractive on-chip optical platform for realizing quantum mechanical concepts in electrodynamics and further developing non-Hermitian photonics. In such systems, an intercavity interaction is often considered as a key parameter to understand the system's behaviors but its estimation/calculation is typically limited for some simplified systems owing to extended complexities. For example, multi-coupled photonic crystal (PhC) nanocavities exhibiting strong resonances with a large free spectral range can serve as an excellent test-bed to study non-Hermitian optical properties when spatially non-uniform gain is introduced. However, the detailed quantitative analysis such as spectral tracing of cavity normal modes is often limited in commercially available numerical tools because of the required massive computation resources. Herein, we report on a concept of spatial overlap integrals (SOIs) between the eigenmodes in non-coupled PhC nanocavities and utilize them to obtain the intercavity interactions in passively coupled PhC nanocavity systems. With the help of coupling strength factors calculated from SOIs, we were able to fully exploit the coupled mode theory (CMT) and readily trace the detailed spectral behaviors of normal modes in various multi-coupled PhC nanocavities. Full-wave numerical simulation results verified the proposed method, revealing that the characteristics of original eigenmodes from non-coupled PhC nanocavities can act as key building blocks for analyzing the normal modes of multi-coupled PhC nanocavities. We further applied this SOI method to various multi-coupled PhC nanocavities with non-symmetric optical gain/loss distributions and successfully observed the unusual spectral evolution of normal modes and the correspondingly occurring unique non-Hermitian behaviors. [ABSTRACT FROM AUTHOR]

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The theoretical understanding of the magneto‐structural correlations of an oximato‐bridged dinuclear copper(II) complex can help develop new applied molecular magnets. This study evaluated the magnetic coupling constant of a [Cu2(hfac)2(ppko)2] complex using the density functional theory combined with the broken symmetry approach (DFT‐BS). The magnetic structure correlation between the magnetic coupling constant (Jcalc) of the complex and the structural parameters, NOCu bond angle (α), ONCu bond angle (β), NO bond length (RN‐O), and Cu•••Cu distance (R0), was evaluated. The data showed that Jcalc initially decreased and then increased as bond angles α and β increased. These relationships were expressed by unary quadratic functions. However, Jcalc varied linearly with the bond length, RN‐O, and spacing, R0. Moreover, in the ground state, the magnetic coupling constant increased with a decrease in the spin density of Cu(1), but gradually decreased as the spin density of Cu(2) increased. An increase of parameters α, β, RN‐O, and R0, resulted in a gradual increase in the distance between Cu(II) ions, and the square of the overlap integral between the non‐orthogonal magnetic orbitals of Cu(II) ions to gradually decay. Finally, the contribution of the antiferromagnetic part decreased as the magnetic coupling constant gradually increased. [ABSTRACT FROM AUTHOR]

The change in the shape of the spectra of a quasi-2D semiconductor under the action of resonant irradiation of the frequency Ω, which is determined by the condition 0 ≤ h.Ω-Eg<g, is considered. The studies showed three types of such a changes. They were analysed in the two cases: a) depending on Ω at fixed parameters of the quasi-2D semiconductor bands (effective masses mc, mh of electrons and holes in the plane of layers, overlap integrals βc, βh) and b) vice versa, when the band parameters change at fixed Ω. The decisive role of βc, βh in the manifestation of one or another of the three types of the spectrum shape change is indicated. [ABSTRACT FROM AUTHOR]

Conduction and valence band states for the highly mismatched alloy (HMA) Ge:C are projected onto Ge crystal states, Ge vacancy states, and Ge/C atomic orbitals, revealing that substitutional carbon not only creates a direct bandgap but also the new conduction band is optically active. Overlap integrals of the new Ge:C conduction band state with states from unperturbed Ge show that the new band cannot be attributed to any single Ge band but is a mixture of multiple Ge states. The Ge Γ conduction band valley state plays the largest single role, but L and X valley states collectively contribute a larger share than Γ due to the multiplicity of degenerate states. C sites structurally resemble uncharged vacancies in the Ge lattice, similar to Hjalmarson's model for other HMAs. C also perturbs the entire Ge band structure even at the deepest crystal core energy levels, particularly if staggered supercells are used to mimic a disordered alloy. Projection onto atomic sites shows a relatively weak localization compared with other HMAs, but it does show a strong anisotropy in probability distribution. L-valley conduction band states in Ge contribute to the conduction band minimum in Ge:C, but the optical transition strength in Ge:C remains within a factor of 2 of the direct gap transition in Ge. [ABSTRACT FROM AUTHOR]

Herein, we present a tunable axial power factor ( P z z ) in a nondegenerate fluorine-doped single-walled carbon nanotube (FSWCNT) using a tractable analytical approach. We derived the expressions for the electrical conductivity (σ), thermopower (α), and power factor (P) as a function of temperature. Additionally, we investigated the influence of doping concentration (n o), constant electric field (E o), and overlapping integrals (Δ s and Δ z) on their behavior. The intensity of the axial power factor ( P z z ) and the operational temperature range can be tuned using the constant electric field, doping (carrier), and overlapping integrals, respectively. Applying the temperature field to the FSWCNT induces high-frequency carrier dynamics that critically depend on the magnitude of the temperature gradient. There exist two dynamic regimes that depend on the temperature gradient and carrier's initial position. The carrier drifts through the FSWCNT and is allowed to perform drifting periodic orbits (in THz frequencies), resulting in the resonant enhancement of P z z . Alternatively, inducing Bloch-like oscillations (in THz frequencies) cause ultra-high negative differential velocity without domain formation using an adequate temperature field. Moreover, we compare the P z z of the FSWCNT to that of the superlattice (SL) ( P z z S L ), which shows that the P z z of the FSWCNT is 8 orders of magnitude greater than that of the SL. It is worth noting that the large P z z obtained and the ability to tune the FSWCNT to operate at high temperatures make the FSWCNT a potential candidate for thermoelectric applications. [ABSTRACT FROM AUTHOR]

The assignment of vibrational states is an integral part of quantum chemical calculations, which supports the analysis of experimental infrared spectra. In variational calculations, usually, it is the leading coefficient of the configuration interaction vector, which provides the state identity. However, this concept will possibly fail in case of special coordinate systems, such as, for example, localized normal coordinates, or within calculations for overtones of non-Abelian molecules, when a real valued configuration basis has been employed. A combination of both renders a proper assignment fairly tedious. We present a route to overcome this problem by using a highly efficient calculation of multidimensional overlap integrals based on the Smolyak quadrature. Beside this, a general protocol for the symmetry assignment of vibrational states will be discussed, which completes a general assignment. Extensive benchmark calculations are provided for the fundamental modes and overtones of chloromethane, CH3Cl, in canonical and localized normal coordinates based on accurate potential energy surfaces obtained from explicitly correlated coupled-cluster theory. In addition, the linear CNNC molecule has been studied, for which hardly any reference data do exist. [ABSTRACT FROM AUTHOR]

The overlap function is an important class of aggregation function that is closely related to the continuous triangular norm. It has important applications in information fusion, image processing, information classification, intelligent decision-making, etc. The usual multi-attribute decision-making (MADM) is to select the decision object that performs well on all attributes (indicators), which is quite demanding. The MADM based on fuzzy quantifiers is to select the decision object that performs well on a certain proportion or quantification (such as most, many, more than half, etc.) of attributes. Therefore, it is necessary to study how to express and calculate fuzzy quantifiers such as most, many, etc. In this paper, the Sugeno integral based on the overlap function (called the O-Sugeno integral) is used as a new information fusion tool, and some related properties are studied. Then, the truth value of a linguistic quantified proposition can be estimated by using the O-Sugeno integral, and the O-Sugeno integral semantics of fuzzy quantifiers is proposed. Finally, the MADM method based on the O-Sugeno integral semantics of fuzzy quantifiers is proposed and the feasibility of our method is verified by several illustrative examples such as the logistics park location problem. [ABSTRACT FROM AUTHOR]

This study investigates the feasibility of using silicon carbide-based layered surface acoustic wave (SAW) devices in acousto-optic applications. The acousto-optic properties of the temperature-stable layered structure TeO3/SiC/128oY-X LiNbO3 are investigated through theoretical analysis. This analysis includes the evaluation of key parameters such as the overlap integral, figure of merit, and diffraction efficiency. The SAW propagation characteristics and field profiles required for these calculations are obtained using SAW software. Results show that the layered structure has high diffraction efficiency of nearly 96% and a promising value for the acousto-optic figure of merit, indicating potential use in low driving power acousto-optic devices. The study concludes that the 3CeSiC-based layered structure possesses excellent acousto-optic properties and has potential for use in acousto-optic devices that can withstand harsh environmental conditions. [ABSTRACT FROM AUTHOR]

Constructing highly twisted and rigid donor–acceptor systems is important for obtaining highly efficient thermally activated delayed fluorescence (TADF) emitters. In the traditional framework of structurally twisted charge‐transfer TADF molecular design, increasing the rigidity of the molecule through constructing rigid groups guarantees the minimized overlap integral between their highest occupied molecular orbitals and lowest unoccupied molecular orbitals for a small singlet and triplet energy gap, which ensures efficient reverse intersystem crossing. Increasing rigidity also prevents the molecule from deforming when in the excited state, effectively suppresses non‐radiative energy dissipation, and improves the photoluminescence quantum yield. As one of the important fragments for TADF emitters, the development of acceptor units with rigid structure deserves in‐depth understanding. Therefore, this review offers a comprehensive summary of the designs and developments of rigid TADF acceptors with "intramolecular locks" including covalent bonds, coordination bonds, and non‐covalent bonds, via the intramolecular‐locking strategy. The mechanism of TADF based on results from density functional theory is also described. Finally, the role of the intramolecular‐locking strategy in the construction of pure organic TADF emitters with rotation‐restricted acceptors and in improving the efficiency of all‐organic TADF‐based organic light‐emitting diodes is discussed. [ABSTRACT FROM AUTHOR]

Recently, amorphous oxide semiconductors have gained significant interest due to their low-temperature processability, high mobility, and high areal uniformity for display backplanes and other large area applications. A multication amorphous oxide, amorphous indium gallium zinc oxide (a-IGZO), has been extensively researched and is now being used in commercial applications. It has been proposed that, in a-IGZO semiconductors, overlapping In-5s orbitals form the conduction path and the carrier mobility is limited due to the presence of multiple cations, which creates a potential barrier for the electronic transport. A multianion approach toward amorphous semiconductors has been suggested to overcome this limitation, and has been shown to achieve Hall mobilities up to an order of magnitude higher compared to multication amorphous semiconductors. In the present work, we compare the electronic structure and electronic transport in a multication amorphous semiconductor, a-IGZO, and a multianion amorphous semiconductor, amorphous zinc oxynitride (a-ZnON) using computational methods. Our results show that, in a-IGZO, the carrier transport path is through the overlap of outer s-orbitals of mixed cations, whereas, in a-ZnON, the transport path is through the overlapping Zn-4s orbitals, which is the only type of metal cation present. We also show that for multicomponent ionic amorphous semiconductors, the electron transport can be explained in terms of the orbital overlap integral, which can be calculated simply from the structural information. The orbital overlap integral has a direct correlation with the carrier effective mass, which is calculated using computationally expensive first-principles density functional theory based methods. [ABSTRACT FROM AUTHOR]

The theory of generalized charges is an asymptotic approximation of quantum mechanics for interatomic forces. It is based on the model of multicomponent electron gas, which extends the Thomas–Fermi model of inhomogeneous electron gas to pair electronic states. The present research takes in consideration the participation of the field of generalized charges in interatomic bonds. Herein, the definition of generalized charges (GC) by means of the overlap integral of the wave functions of valence electrons is given, and properties of GC are found out. Equations are derived for the potential and length of a homopolar bond, and dependence of these parameters on the generalized charges is shown. The dissociation energy of a diatomic molecule is expressed in terms of the nuclear charges, the function and multiplicity of the covalent bond, the angular momentum, and the vibrational energy of the binding electrons. The parametrization rules are substantiated and an a priori calculation of the dissociation energy of diatomic homonuclear molecules is carried out against the electronic configuration of the bond electrons and the nuclear charge. The calculation results for homonuclear compounds of the elements of the first four rows of the periodic table are shown to be of satisfactory accuracy. [ABSTRACT FROM AUTHOR]

Energy level interaction and electron concentration are crucial aspects that affect the response performance of quantum cascade detectors (QCDs). In this work, two different-structured array QCDs are prepared, and the detectivity reaches 109 cm·Hz1/2/W at room temperature. The overlap integral (OI) and oscillator strength (OS) between different energy levels under a series of applied biases are fitted and reveal the influence of energy level interaction on the response performance. The redistribution of electrons in the cascade structure at room temperatures is established. The coupled doped-well structure shows a higher electron concentration at room temperature, which represents a high absorption efficiency in the active region. Even better responsivity and detectivity are exhibited in the coupled doped-well QCD. These results offer a novel strategy to understand the mechanisms that affect response performance and expand the application range of QCDs for long-wave infrared (LWIR) detection. [ABSTRACT FROM AUTHOR]

The conventional approach to optimising plasmonic sensors is typically based entirely on ensuring phase matching between the excitation wave and the surface plasmon supported by the metallic structure. However, this leads to suboptimal performance, even in the simplest sensor configuration based on the Otto geometry. We present a simplified coupled mode theory approach for evaluating and optimizing the sensing properties of plasmonic waveguide refractive index sensors. It only requires the calculation of propagation constants, without the need for calculating mode overlap integrals. We apply our method by evaluating the wavelength-, device length- and refractive index-dependent transmission spectra for an example silicon-on-insulator-based sensor of finite length. This reveals all salient spectral features which are consistent with full-field finite element calculations. This work provides a rapid and convenient framework for designing dielectric-plasmonic sensor prototypes—its applicability to the case of fibre plasmonic sensors is also discussed. [ABSTRACT FROM AUTHOR]

A monomeric sensor, TagRFP-23-Ultramarine (TR-23-U), for effector caspase-3 was obtained. The overlap integrals of new pairs of red fluorescent protein TagRFP with four chromoproteins were calculated. The monomeric state of the Ultramarine protein and the TR-23-U sensor was confirmed by gel filtration chromatography and dynamic light scattering. Incubation with caspase-3 showed the possibility of using the new fusion protein as a FRET sensor for apoptosis detection. [ABSTRACT FROM AUTHOR]

[Display omitted] • There is the physical quantity σ → · (p → + A →) V σ → · (p → + A →) in the Hamiltonian of the matrix Dirac equation. • The precision of the STO-30G is less than one significant figure for the quantity given by i σ → · (p → × V A → + V A → × p →) in the Gauss-type charge density distribution model. • As seen in Table 3, the precision calculated even with the STO-30G is less than one significant figure for the quantity given by i σ → · (p → × V A → + V A → × p →) in the homogenous charge density distribution model, although it is 13 significant figures for the overlap integral as seen in Table 2. • With the present numerical results, we can conclude that to use the GTO is not suitable for the calculation of the physical quantity given by i σ → · (p → × V A → + V A → × p →). Numerical calculations are performed for a physical quantity which is appearing in the Hamiltonian of the matrix Dirac equation with containing the vector potential of the magnetic field due to the nuclear spin and with considering the restricted magnetic balance. This quantity is necessary for the relativistic calculation of the nuclear-magnetic-resonance spectra. It is shown that to use Gaussian-type orbital is not suitable for the calculation of this quantity. [ABSTRACT FROM AUTHOR]

The rigorous formula of overlap integrals of continuum stationary states with their asymptotic expressions in potentials of finite widths are derived. Those of energies E 1 and E 2 consist of diagonal terms that are proportional to δ (E 1 − E 2) and nondiagonal terms. Owing to the composition of nondiagonal terms, superpositions of stationary states have time-dependent norms and finite probability currents. These do not represent isolate states. In various exceptional potentials and in free theory, nondiagonal terms do not exist, and the superpositions of states with different energies represent isolate particles that exactly describe scattering processes. [ABSTRACT FROM AUTHOR]

Analytical gradients of variational two-electron reduced-density matrix (2-RDM) methods are derived by transforming the atomic-orbital reduced-density matrices to remove the dependence of the N-representability conditions on the orbital-overlap matrix. The transformation, performed through a Cholesky decomposition of the geminal-overlap matrix, generates a Hellmann-Feynman-like expression for the gradient that only depends on the derivative of the transformed reduced Hamiltonian matrix. The formulation is applicable not only to the variational 2-RDM method but also to variational wavefunction methods like the full configuration interaction and complete active-space self-consistent-field. To illustrate, we apply the analytical gradients to perform geometry optimizations on several transition metal complexes, octahedral and trigonal prismatic CrF6 as well as the (ethylene-1,2-dithiolato)nickel, or Ni(edt)2, complex. [ABSTRACT FROM AUTHOR]

The bonding situation in the intermetallic compounds LaBeGe and ThBeGe were investigated using the wavefunctions generated from the all‐electron relativistic density functional calculations. Following the quantum theory of atoms in molecules (QTAIM) the atomic basins were determined from the electron density and the effective charges computed. These were also compared to corresponding charges for the procrystal density. The bonding was analyzed utilizing the delocalization indices (DIs) computed from the overlap integrals over the QTAIM basins. The analysis was extended by the evaluation of the electron localizability indicator (ELI‐D) and completed by the calculation of DIs for the ELI‐D basins. [ABSTRACT FROM AUTHOR]

We develop a semi-microscopic model to describe transfer reactions. For the sake of simplicity, we focus on nucleon-transfer reactions, but the theory can be generalized to other transfer processes. The model makes use of overlap integrals computed in the microscopic Resonating Group Method (RGM). This technique is based on an effective nucleon-nucleon interaction and on the cluster approximation. It avoids the choice of a nucleon-core potential for the residual nucleus, and does not require any fit of spectroscopic factors. The model is therefore free of parameter. For the entrance channel, we use the Continuum Discretized Coupled Channel (CDCC) method where the breakup of the projectile is simulated by approximations of the continuum. This technique is well known for elastic scattering and for breakup reactions. It is well adapted to weakly bound nuclei such as the deuteron. The model is applied to the 14 C (d , p) 15 C and 6 He (d , n) 7 L i reactions with RGM wave functions of 15 C and of 7 Li. The 15 C nucleus is described by 14 C (0 + , 2 +) + n configurations whereas 7 Li contains the α + t , 6 He (0 +) + p and 6 Li (1 + , 0 +) + n configurations. The spectroscopic factors are in fair agreement with the literature. We show that the model provides an excellent description of the transfer cross sections considering that no parameter is adjusted. [ABSTRACT FROM AUTHOR]

In this study, we have synthesised two novel p-type organic semiconductors in which chalcogen atoms are introduced along the long axis of molecules: 2-(pyran-4-ylidene)-1,3-benzodithiole (P-BT) and 2-(thiopyran-4-ylidene)-1,3-benzodithiole (TP-BT). P-BT forms a conventional two-dimensional (2D) herringbone arrangement, while TP-BT forms a similar herringbone arrangement, but also includes overlap integrals between the herringbone layers, realising isotropic three-dimensional (3D) intermolecular interactions. We have fabricated bottom-gate/top-contact organic thin-film transistors (OTFTs) using these materials as the active layers and have investigated the film thickness dependence of their mobility. The results demonstrate that the mobility of 2D P-BT decreases as the thickness of the active layer increases. In contrast, the mobility of the 3D TP-BT does not change as the film thickness increases, and the corresponding OTFTs have little film thickness dependence. Further results regarding the thickness dependence of the contact resistance estimated by the transfer line method indicate that TP-BT can significantly suppress access resistance due to its 3D electronic structure. [ABSTRACT FROM AUTHOR]

Ensembles of classifiers have been receiving much attention lately, they consist of a collection of classifiers that process the same information and their output is combined in some manner. The combination method is probably the most important part in a ensemble of classifiers however, many works found in literature focus mostly on the classification step, using simple approaches on the combination step, such as majority voting. In this paper, we propose a new combination method based on a generalization of discrete Choquet integrals, combining it with quasi overlap functions to aggregate the outputs of classifiers in an ensemble. We also tested the proposed combination approach in a simple ensemble against other methods in literature to verify if there was a significant gain in performance. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C3N4) is a low-cost photocatalyst with high stability and many applications. However, the photocatalytic activity of g-C3N4 has been limited due to its low visible light absorption and high electron–hole pair recombination rate. In this study, the effect of S, P, and O doping on the geometrical and electronic properties of the g-C3N4 is investigated using density functional theory (DFT) calculations. The results showed that the surface area increased in the cases of the S- and P-doped systems. Electron density distribution of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular (LUMO), and natural bond orbital (NBO) analyses illustrated that among the S- and O-doped systems, Sint- and Oint-doped g-C3N4 quantum dots structures had high delocalization. Delocalization of electrons increased after non-metal doping at the edge site. Phosphorus doping at the Nedge site led to a stronger donor–acceptor interaction. The most stable configuration was related to doping at the edge (S- and O-doped) and corner carbon (P-doped) sites. The changes in the Gibbs energy are 1.42, -1.15, and -23.03 eV, respectively. According to the results of time-dependent density-functional theory (TD-DFT) calculations, the Sed- and PC-doped g-C3N4 quantum dots represent a higher light-harvesting ability and the values of light-harvesting efficiency of these structures are 0.10 and 0.031, respectively. Moreover, the Sed-CN and PC-CN have less overlap integral than g-C3N4 quantum dots (CNQDs), while Oed-doped CN has a greater light-harvesting ability (0.14) than that of CNQDs (0.0082). On the basis of the results, non-metal doping increased visible light-harvesting and lifetime of the e−–h+ pair, which led to increased photocatalytic molecular descriptors. [ABSTRACT FROM AUTHOR]

CdS quantum dots prepared by the Langmuir–Blodgett method have been investigated using UV spectroscopy and time-resolved photoluminescence. It has turned out that at temperatures 5–300 K, most prominent features in photoluminescence spectra are an intense high-energy peak and a wide low-energy shoulder. The high-energy peak observed in the spectra is due to transitions between states in the valence and conduction bands, and the wide shoulder is associated with defects in quantum dots. The kinetics of band-edge photoluminescence is biexponential, which is interpreted as the simultaneous recombination of negative excitons and trions. It has been found that trion recombination makes a major contribution to the photoluminescence intensity. It has been shown that the recombination rate of both excitons and trions drops with increasing temperature. The slowdown of exciton recombination is attributed to the thermal occupation of higher lying optically inactive states and is well described in terms of the available theoretical models of the exciton state fine structure. The radiative lifetime of trions grows with temperature owing, first, to the occupation of optically passive states and, then, to delocalization of one electron from the quantum dot into the overbarrier continuum of states, which decreases the overlapping integral. [ABSTRACT FROM AUTHOR]

Excitation energy transfer is a ubiquitous process of fundamental importance for understanding natural phenomena, such as photosynthesis, as well as advancing technologies ranging from photovoltaics to development of photosensitizers and fluorescent probes used to explore molecular interactions inside living cells. The current version of PyFREC 2.0 is an advancement of the previously reported software (D. Kosenkov, J. Comput. Chem.2016, 37, 1847–1854). The current update is primarily focused on providing a computational tool based on Förster theory for bridging a gap between theoretically calculated molecular properties (e.g., electronic couplings, orientation factors, etc.) and experimentally measured emission and absorption spectra of molecules. The software is aimed to facilitate deeper understanding of photochemical mechanisms of fluorescence resonance energy transfer (FRET) in donor–acceptor pairs. Specific updates of the software include implementations of overlap integrals between donor emission and acceptor absorption spectra of FRET pairs, estimation of Strickler–Berg fluorescence lifetimes, calculation of Förster radii, energy transfer efficiency, and radiation zones that, in particular, determine applicability of the Förster theory. [ABSTRACT FROM AUTHOR]

Paramagnetic complexes that possess magnetically switchable properties show promise in a number of applications. A significantly underdeveloped approach is the use of metallocages, whose magnetic properties can be modulated through host–guest chemistry. Here we show such an example that utilises a simple [CuII2L4]4+ lantern complex. Magnetic susceptibility and magnetisation data shows an absence of exchange in the presence of the diamagnetic guest triflate. However, replacement of the bound triflate by ReBr62− switches on antiferomagnetic exchange between the Cu and Re ions, leading to an S = 1/2 ground state for the non-covalent complex [ReBr62−⊂CuII2L4]2+. Comparison of this complex to a "control" palladium-cage host–guest complex, [ReBr62−⊂PdII2L4]2+, shows that the encapsulated ReBr62− anions retain the same magnetic anisotropy as in the free salt. Theoretically calculated spin-Hamiltonian parameters are in close agreement with experiment. Spin density analysis shows the mode of interaction between the CuII and ReIV centres is through the Re-Br⋯Cu pathway, primarily mediated through the Cu(dx2−y2)‖Brsp‖Re(dyz) interaction. This is further supported by overlap integral calculations between singly occupied molecular orbitals (SOMOs) of the paramagnetic ions and natural bonding orbitals analysis where considerable donor-to-acceptor interactions are observed between hybrid 4s4p orbitals of the Br ions and the empty 4s and 4p orbitals of the Cu ions. [ABSTRACT FROM AUTHOR]

Semiconductor quantum dots, due to their unique optical properties, are promising materials for the design of optoelectronic devices. At the same time, the parameters of instruments significantly depend both on the band structure and the impurity energy levels in quantum dots. In this regard, the electron–phonon interaction acts as the most important mechanism of temperature shift in energy levels. The aim of the present work was to theoretically study how the electron–phonon interaction influences the temperature dependence of radiative recombination in an impurity complex in a semiconductor quasi-zero-dimensional structure. The effect of temperature on the energy levels in a semiconductor quantum dot was theoretically considered by the statistics method assuming that the electron–phonon interaction makes the main contribution to the temperature dependence. The dispersion equation defining the hole binding energy in the impurity complex in a spherically symmetric quantum dot was obtained in terms of the adiabatic approximation in the zero-range potential model. The spectral intensity of recombination radiation in the quasi-zero-dimensional structure with impurity complexes was calculated in the dipole approximation taking into account the radius dispersion of quantum dots. Temperature curves were plotted for the case of InSb-based quantum dots. The temperature dependence of the binding energy in the complex was calculated for different values of the quantum-dot radius. The hole binding energy was shown to decrease with an increase in temperature, which was due to a temperature spreading of the wave function of a quasi-steady A+ state under the conditions of electron–phonon and hole–phonon interactions. The bond energy of the A+ state was found to increase with a decrease in the quantum-dot radius due to an increase in the ground state energy of the adiabatic electron potential. The spectral intensity of recombination radiation was calculated as a function of the transition energy for different temperature values. It was found that, with an increase in temperature, the threshold transition energy shifts to the short-wave spectral region and thermal quenching of the recombination radiation occurs. This was due to a decrease in the overlap integral of the wave functions of initial and final electron states because of the transition energy increase. The effect of the electron–phonon interaction on recombination processes in the impurity complex in spherically symmetric quantum dot is manifested in temperature quenching of the recombination radiation spectral intensity. The effect of coming to a plateau appears to be common for different mechanisms of photoluminescence. [ABSTRACT FROM AUTHOR]

In this study, we incorporated nanometal surface energy transfer (NSET) in lateral flow immunoassay (LFIA) and explored the relationship between fluorescence quenching efficiency and detection sensitivity to improve sensitivity of NSET-LFIA system. We developed nine gold nanoparticles (GNPs) with absorption spectrum in the range of 520–605 nm as acceptors and quantum dot microspheres (QDMs) with emission spectrum of 530, 570, and 610 nm as donors. By analyzing the overlap integral area, fluorescence quenching efficiency, and detection sensitivity of 27 donor-acceptor pairs, we observed that the larger overlap integral area led to higher fluorescence quenching efficiency and detection sensitivity. A maximum fluorescence quenching efficiency of 91.0% was obtained from the combination of GNPs at 605 nm and QDMs at 610 nm, achieving the highest detection sensitivity. We developed NSET-LFIA for the detection of T2 toxin with a limit of detection of 0.04 ng/mL, which was 10-times higher than that obtained via conventional GNP-LFIA. NSET-LFIA represents a versatile, ultrasensitive and valuable screening tool for small molecules in real samples. [Display omitted] [ABSTRACT FROM AUTHOR]

• FRET from bovine pancreas trypsin to coumarin 440 dye is presented. • Trypsin is key enzyme for absorption and digestion of nutrients in small intestine. • Conformational changes in trypsin on interaction with C440 studied by molecular docking. • Trypsin-coumarin 440 complex formed via dynamic quenching, inhibits activity of trypsin. • Thermodynamic parameters validate hydrophobic, spontaneous, exothermic process in trypsin@C440 conjugate. Herein, a systematic investigation of energy transfer from bovine pancreas trypsin to coumarin 440 (C440) dye is presented with an aim to design a FRET probe, as trypsin is an important enzyme for absorption and digestion of nutrients in the small intestine. Conformational changes in trypsin upon interaction with C440 dye are studied by employing both spectroscopic and molecular docking techniques. Steady state and time resolved measurements validate the formation of trypsin-C440 complex via dynamic quenching, that confirms the role of C440 as an inhibitor to suppress the activity of trypsin. Spectral overlap integral, Förster's distance, rate and energy transfer efficiency are calculated from steady state measurements. The observed blue shift in fluorescence suggests conformational changes due to hydrophobicity that arises in trypsin structure on binding with C440 possibly due to their interaction through H-bond (SER195 and GLN192), hydrophobic (GLN192 and HIS57) and π-π stacking bonding (HIS57). The stability of trypsin@C440 bio-conjugate at higher temperature was established from temperature dependent PL studies and the thermodynamic parameters determined agree with second law of thermodynamics. The thermodynamic parameters such as change in enthalpy ( Δ H = 172.2 J mo l − 1 ) , change in entropy ( Δ S = 15.3 J mo l − 1 K − 1 ) and the respective approximately same and unity values of Gibb's free energy (Δ G) and Hill coefficient (n), as well as binding affinities determined from temperature dependent fluorescence studies validate the hydrophobic, spontaneous, exothermic process engaged in trypsin@C440 bio-conjugate. FRET from Trypsin to Coumarin440 dye and their interactions [Display omitted] [ABSTRACT FROM AUTHOR]

We analyze the topological properties of a family of generalized Su-Schrieffer-Heeger (SSH) chains and mesh geometries. In both the geometries the usual staggering in the distribution of the two overlap integrals is delayed (in space) by the inclusion of a third (additional) hopping term. A tight-binding Hamiltonian is used to unravel the topological phases, characterized by a topological invariant. While in the linear chains, the topological invariant (the Zak phase) always appears to be quantized, in the quasi-one dimensional strip geometries and the generalized SSH mesh patterns the quantization of the Zak phase is sensitive to the strength of the additional interaction (the 'extra' hopping integral). We study its influence thoroughly and explore the edge states and their robustness against disorder in the cross-linked generalized SSH mesh geometries. The systems considered here can be taken to model (though crudely) two-dimensional polymers where the cross-linking brings in non-trivial modification of the energy bands and transport properties. In addition to the topological features studied, we provide a prescription to unravel any flat , non-dispersive energy bands in the mesh geometries, along with the structure and distribution of the compact localized eigenstates. Our results are analytically exact. • We analyze the topological properties of a family of generalized Su-Schrieffer-Heeger (SSH) chains and mesh geometries. • The usual staggering in the distribution of the two overlap integrals is delayed by the inclusion of a third hopping term. • In the generalized SSH mesh patterns the quantization of the Zak phase is sensitive to the strength of the additional interaction. • We study its influence thoroughly and explore the edge states and their robustness against disorder. [ABSTRACT FROM AUTHOR]