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The multiple metastable excited states provided by excited‐state intramolecular proton transfer (ESIPT) molecules are beneficial to bring temperature‐dependent and color‐tunable long persistent luminescence (LPL). Meanwhile, ESIPT molecules are intrinsically suitable to be modulated as D‐π‐A structure to obtain both one/two‐photon excitation and LPL emission simultaneously. Herein, we report the rational design of a dynamic CdII coordination polymer (LIFM‐106) from ESIPT ligand to achieve the above goals. By comparing LIFM‐106 with the counterparts, we established a temperature‐regulated competitive relationship between singlet excimer and triplet LPL emission. The optimization of ligand aggregation mode effectively boost the competitiveness of the latter. In result, LIFM‐106 shows outstanding one/two‐photon excited LPL performance with wide temperature range (100–380 K) and tunable color (green to red). The multichannel radiation process was further elucidated by transient absorption and theoretical calculations, benefiting for the application in anti‐counterfeiting systems. [ABSTRACT FROM AUTHOR]

Isomeric states were observed in nuclei produced in an experiment at the RIKEN Nishina Center Radioactive Isotope Beam Factory following the in-flight fission of a 345 MeV/nucleon 238 U beam. Isomers reported in nuclei spanning a predicted prolate-oblate shape change boundary, 111 Zr ( E = 283.1 keV; τ = 0.326 (63) μ s), 112 Nb ( E = 44.2 keV; τ = 0.094 (26) μ s), 113 Nb ( E = 135.4 keV; τ = 0.846 (80) μ s), and 115 Mo ( E = 198.6 keV; τ = 63 (4) μ s), are compared to potential-energy surface calculations which gave a selection of low-lying configurations for each nucleus. Tentative assignments of ground and excited states were made based on energy similarities to the calculations, reduced transition probabilities of the decays, and constraints of transition multipolarities from γ -ray coincidence measurements. These assignments are suggestive of significant deformation being persistent for N > 70 in this region. In addition, isomers in 108 Nb, 109 Nb, 113 Tc, 117 Ru, 119 Ru, 120 Rh, and 122 Rh, not spanning the prolate-oblate transition discussed, are presented. [ABSTRACT FROM AUTHOR]

We report on the characterisation of the lowest three electronic states of MgKr + , the X + 2 Σ + ground state associated with the Mg + (3s) 2 S 1 / 2 + Kr(4p) 6 1 S 0 dissociation limit and the A + 2 Π Ω (Ω = 1 / 2 , 3 / 2) and B + 2 Σ + excited states associated with the Mg + (3p) 2 P 1 / 2 , 3 / 2 + Kr(4p) 6 1 S 0 dissociation limits. The vibrational structure of the X + ground state was measured by pulsed-field-ionisation zero-kinetic-energy photoelectron spectroscopy starting from the a 3 Π 0 metastable state of MgKr generated by laser ablation of a Mg rod in a Kr supersonic beam. The vibrational assignment was derived from the isotopic structure of the spectra and the adiabatic ionisation energy of the a → X + ionising transition was determined to be 38182.4(2.0) cm − 1 . Partially rotationally resolved spectra of the A + ← X + and B + ← X + transitions were recorded by monitoring the yield of Mg + ions produced by dissociation of MgKr + using the technique of isolated-core Rydberg-dissociation spectroscopy. Analytical potential-energy functions of the X + , A + , and B + states were derived using a global model of these states that includes the spin-orbit interaction. The observation of the highest vibrational levels of the B + state and the onset of the Kr + Mg + (3p) dissociation continuum enabled the precise determination of the dissociation energies of the X + , A + and B + states of MgKr + and of the a state of MgKr. The X + , A + and B + states of MgKr + are important stepping stones to access the Rydberg states of MgKr + and the ground state of MgKr 2 + by resonant multiphoton excitation. [ABSTRACT FROM AUTHOR]

We report on the characterisation of the lowest three electronic states of MgKr + , the X + 2 Σ + ground state associated with the Mg + (3s) 2 S 1 / 2 + Kr(4p) 6 1 S 0 dissociation limit and the A + 2 Π Ω (Ω = 1 / 2 , 3 / 2) and B + 2 Σ + excited states associated with the Mg + (3p) 2 P 1 / 2 , 3 / 2 + Kr(4p) 6 1 S 0 dissociation limits. The vibrational structure of the X + ground state was measured by pulsed-field-ionisation zero-kinetic-energy photoelectron spectroscopy starting from the a 3 Π 0 metastable state of MgKr generated by laser ablation of a Mg rod in a Kr supersonic beam. The vibrational assignment was derived from the isotopic structure of the spectra and the adiabatic ionisation energy of the a → X + ionising transition was determined to be 38182.4(2.0) cm − 1 . Partially rotationally resolved spectra of the A + ← X + and B + ← X + transitions were recorded by monitoring the yield of Mg + ions produced by dissociation of MgKr + using the technique of isolated-core Rydberg-dissociation spectroscopy. Analytical potential-energy functions of the X + , A + , and B + states were derived using a global model of these states that includes the spin-orbit interaction. The observation of the highest vibrational levels of the B + state and the onset of the Kr + Mg + (3p) dissociation continuum enabled the precise determination of the dissociation energies of the X + , A + and B + states of MgKr + and of the a state of MgKr. The X + , A + and B + states of MgKr + are important stepping stones to access the Rydberg states of MgKr + and the ground state of MgKr 2 + by resonant multiphoton excitation. [ABSTRACT FROM AUTHOR]

We explore the rich nature of correlations in the ground state of ultracold atoms trapped in state-dependent optical lattices. In particular, we consider interacting fermionic ytterbium or strontium atoms, realizing a two-orbital Hubbard model with two spin components. We analyze the model in one-dimensional setting with the experimentally relevant hierarchy of tunneling and interaction amplitudes by means of exact diagonalization and matrix product states approaches, and study the correlation functions in density, spin, and orbital sectors as functions of variable densities of atoms in the ground and metastable excited states. We show that in certain ranges of densities these atomic systems demonstrate strong density-wave, ferro- and antiferromagnetic, as well as antiferroorbital correlations. [ABSTRACT FROM AUTHOR]

We discuss peculiar features of electron scattering on the N2 molecule and the N2+ ion, that are important for modeling plasmas, Earth's and other planets' atmospheres. These features are, among others: the resonant enhancement of the vibrational excitation in the region of the shape resonance around 2.4 eV, the resonant character of some of electronic excitation channels (and high values of these cross sections, both for triplet and singlet states), high cross section for the dissociation into neutrals, high cross sections for elastic scattering (and electronic transitions) on metastable states. For the N2+ ion we discuss both dissociation and the dissociative ionization, leading to the formation of atoms in excited states, and dissociative recombination which depends strongly on the initial vibrational state of the ion. We conclude that the theory became an indispensable completion of experiments, predicting many of partial cross sections and their physical features. We hope that the data presented will serve to improve models of nitrogen plasmas and atmospheres. [ABSTRACT FROM AUTHOR]

The review presents several families of spin crossover (SCO) active Fe(II) coordination compounds with photoactive N-donor heterocyclic ligands, in which the photoinduced structural changes can activate reversible change of spin state and thus control magnetic properties under isothermal conditions. Detailed description of structural, spectral, and magnetic behavior for selected examples of photoisomerizable coordination compounds are provided. From the application point of view, light is an excellent tool to control SCO properties. The first and best known approach called Light Induced Excited Spin State Trapping (LIESST) has a significant technological limitation due to low temperatures (< 120 K) required for the trapping and existence of photoexcited metastable states. The second and more elegant approach known as Ligand-Driven Light-Induced Spin Crossover (LD-LISC) seems to be a very suitable strategy utilizing light-induced structural changes to control the spin. Isomerization of photoswitchable groups, such as azobenzenes or stilbenes, can cause reversible transformation between two isomeric forms after exposition to selective wavelengths at ambient temperature. A very recent third approach, the Guest-Driven Light-Induced Spin Crossover (GD-LISC) effect employing the photoisomerizable guest molecules to control the spin state has also been introduced. [ABSTRACT FROM AUTHOR]

HSP90 are abundant molecular chaperones, assisting the folding of several hundred client proteins, including substrates involved in tumor growth or neurodegenerative diseases. A complex set of large ATP-driven structural changes occurs during HSP90 functional cycle. However, the existence of such structural rearrangements in apo HSP90 has remained unclear. Here, we identify a metastable excited state in the isolated human HSP90α ATP binding domain. We use solution NMR and mutagenesis to characterize structures of both ground and excited states. We demonstrate that in solution the HSP90α ATP binding domain transiently samples a functionally relevant ATP-lid closed state, distant by more than 30 Å from the ground state. NMR relaxation enables to derive information on the kinetics and thermodynamics of this interconversion, while molecular dynamics simulations establish that the ATP-lid in closed conformation is a metastable exited state. The precise description of the dynamics and structures sampled by human HSP90α ATP binding domain provides information for the future design of new therapeutic ligands. To refold client proteins, HSP90 chaperone undergoes large structural rearrangements. Here the authors use NMR and molecular simulation and reveal structure and dynamics of a key functionally relevant metastable state of human HSP90α N-terminal domain. [ABSTRACT FROM AUTHOR]

Nuclear isomers are the metastable excited states of nuclei. The isomers can be categorized into a few classes including spin, seniority, K, shape and fission isomers depending upon the hindrance mechanisms. In this paper, we aim to present an overview of seniority isomers, which is a category related to the seniority quantum number. The discussion is mainly based on the concepts of seniority and generalized seniority. Various aspects of seniority isomers and their whereabouts have been covered along with the situations where seniority mixing prevents the isomerism. [ABSTRACT FROM AUTHOR]

An original technique for describing excited states of electrons in crystal structure has been considered by an example of lithium. It is shown that the electron spectrum in lithium changes only slightly at large values of lattice parameter (up to 8.77 Bohr radii). The lifetimes of excited electrons of external s and p states differ significantly at lattice parameters d < 8.77 Bohr radii. A metastable crystalline state of bcc lithium is found, which barely depends on the excitation power at a lattice constant equal to 6.55 Bohr radii, corresponding to the bcc lattice constant of lithium in the ground state. [ABSTRACT FROM AUTHOR]

A general theoretical approach to modeling electronic excited states based on a non-Hermitian Hamiltonian is proposed. The proposed analytical model has several advantages. Firstly, it allows all excited states to be targeted by specifying a single excitation parameter. Consequently, all states (ground or excited) are treated equally. Secondly, it allows the consideration of excitations of any nature and power. Thirdly, it provides an estimation of the lifetime of the excited states using a unified approach. We provide a theoretical investigation of the new metastable states in carbon monoxide using this approach. Finally, the electronic structure and the decay time of the excited states in carbon monoxide are discussed. • An original method of considering excitations of any nature and power is proposed. • Investigation of the electronic excited states of carbon monoxide is carried out. • The formation of new metastable states of carbon monoxide under external conditions is described. • The lifetime of excited states of carbon monoxide is estimated. [ABSTRACT FROM AUTHOR]

Three iron(II) complexes, [Fe(L1)2(NCS)2(MeOH)2] (1), [Fe(L1)2(NCSe)2(MeOH)2] (2), and [Fe(L2)2(NCS)2]n (3) (L1 = 2,5-dipyridyl-3,4-ethylenedioxythiophene and L2 = 2,5-diethynylpyridinyl-3,4-ethylenedioxythiophene), have been synthesized using redox-active luminescent ethylenedioxythiophene (EDOT)-based ligands, and characterized by variable temperature single-crystal X-ray diffraction, (photo)magnetic, optical reflectivity, and spectroscopy studies. Magneto-structural investigations revealed that 1 and 2 are mononuclear with a FeN4O2 octahedral coordination geometry and remain in a high-spin (HS) (S = 2) state in a temperature range of 2–280 K. Interestingly, a 2D coordination network structure with FeN6 surrounding each iron center was observed for 3, which exhibits reversible thermo-induced spin-state switching between the paramagnetic high-spin (HS) (S = 2) and diamagnetic low-spin (LS) (S = 0) states at around 105 K (T1/2). Furthermore, optical reflectivity and photomagnetic measurements at low temperature confirmed that 3 shows reversible ON/OFF switching between the photoinduced excited paramagnetic HS metastable state and diamagnetic LS state under light irradiation (ON mode using red light and OFF mode using green light). Finally, the photoinduced excited HS state can be reversibly relaxed back to the diamagnetic ground LS state by heating the system at ca. 88 K (TLIESST = 88 K) (light-induced excited spin state trapping (LIESST) effect). Furthermore, 3 also showed an exciting and unique 18 K wide light-induced thermal hysteresis (LITH) effect above liquid nitrogen temperature (100 K). DFT and CASSCF level theoretical calculations were utilized to better understand the magneto-structural correlations of these complexes. [ABSTRACT FROM AUTHOR]

A comprehensive study of electron collisions with the X1Σg+ ground state as well as the metastable A3Σu+ and a1Πg excited states of the N2 molecule is reported using the fixed-nucleus R-matrix method. Integral elastic scattering and electronic excitation cross sections from the X1Σg+ ground state to the eight lowest electronic states, A3Σu+, B3Πg, W3Δu, B′3Σu−, a1Πg, a′1Σu−, w1Δu and C3Πu, overall agree well with the available experimental and theoretical results although updates of some recommended values are suggested. Accurate electron impact electronic transition cross sections starting from the A3Σu+ and a1Πg metastable excited states are reported. The total summed electronic transition cross sections from the a1Πg state is dominant: an order of magnitude higher than those of the X1Σg+ ground state. The de-excitation cross sections generally show a downward trend with increasing incident electron energy, which is different from the elastic and electronic excitation cross sections which generally increase with collision energy. There is a prominent 2Πu symmetry resonance peak at 2.8 eV for electronic de-excitation scattering of a1Πg → B3Πg, which significantly contributes to the total summed cross sections from the a1Πg excited state. The present results provide a new insight which will aid understanding of electron spectra in the atmosphere of the Earth and Titan. [ABSTRACT FROM AUTHOR]

Neither the thermodynamically determined probability isotherm nor its kinetically manifest rate isotherm can be applied to photo-absorptive reactions such that the participants, including photons, may be treated as if they were chemical reactants. Photons and chemical reactants differ from each other fundamentally: firstly, a photon's energy is absolute and, in all instances of practical relevance to the present paper, independent of its surrounding electrochemical field, while the energy of a chemical reactant is relative and defined by its surrounding field; secondly, while both photons and chemical reactants can and do engage in entropy creation, only chemical reactants can engage in entropy exchange. Clarification of these differences requires identification and abandonment of fundamental historical errors in photochemical thought deriving from inappropriate overreach of analogies drawn between light and ideal gases, and including: treatment of photo-absorption as a reversible chemical reaction; attribution to light of thermal potential, or temperature (as distinct from the idealised abstraction of a 'temperature signature'); attribution to light of exchangeable entropy content. We begin by addressing widespread misapprehensions concerning the perennially misunderstood concept of entropy and the frequently overlooked distinction between entropy creation and entropy exchange. Armed with these clarifications, we arrive at a useful perspective for understanding energy absorption and transfer in photosynthetic processes which, through the chemical 'kidnapping' of metastable excited states within structured metabolic pathways, achieves outcomes which the Second Law denies to thermal chemical reactions. [ABSTRACT FROM AUTHOR]

Measurements of emission cross sections for the O + − N 2 collision system with the incident beam of 1–10 keV O + in the ground O + (4 S) and metastable O + (2 D) and O + (2 P) states are reported. The emission cross section induced by incident ions in the metastable state O + (2 P) is much larger than that for the ground O + (4 S) state. The emission cross section of N 2 + ion for (0 , 0) , (0 , 1) , and (1 , 2) bands system is measured and the ratio of intensities for these bands is established as 1 0 : 3 : 1. It is shown that the cross sections for the N + ∗ ions emissions in the dissociative charge exchange processes increase with the increase of the incident ion energy. The energy dependence of the emission cross section of the band (0 , 0) λ = 3 9 1. 4  nm of the first-negative band system of the N 2 + and degree of linear polarization of emission in O + − N 2 collision are measured for the first time. An influence of an admixture of the ion metastable state on a degree of linear polarization is revealed. The mechanism of the processes realized during collisions of ground and metastable oxygen ions on molecular nitrogen have been established. It is demonstrated that for O + − N 2 collision system the degree of linear polarization by metastable O + (2 P) ions is less compared to those that are in the ground O + (4 S) state and the sign of emission of degree of linear polarization of excited molecular ions does not change. [ABSTRACT FROM AUTHOR]

Time‐resolved X‐ray (Tr‐XAS) and optical transient absorption (OTA) spectroscopy on the pico‐microsecond timescale coupled with density functional theory calculations are applied to study the light‐induced spin crossover processes of a Fe‐based macrocyclic complex in solution. Tr‐XAS analysis after light illumination shows the formation of a seven‐coordinated high‐spin quintet metastable state, which relaxes to a six‐coordinated high‐spin configuration before decaying to the ground state. Kinetic analysis of the macrocyclic complex reveals an unprecedented long‐lived decay lifetime of approximately 42.6 μs. Comparative studies with a non‐macrocyclic counterpart illustrate a significantly shortened approximately 568‐fold decay lifetime of about 75 ns, and highlight the importance of the ligand arrangement in stabilizing the reactivity of the excited state. Lastly, OTA analysis shows the seven‐coordinated high‐spin state to be formed within approximately 6.2 ps. These findings provide a complete understanding of the spin crossover reaction and relaxation pathways of the macrocyclic complex, and reveal the importance of a flexible coordination environment for their rational design. [ABSTRACT FROM AUTHOR]

The complex trans‐[RuNO(NH3)4F]SiF6 was synthesized in quantitative yield and the structure was characterized by X‐ray diffraction and spectroscopic methods. The complex crystallizes in the non‐centrosymmetric space group Pn. Hirshfeld surface analysis revealed that the dominant intermolecular interactions are of types H...F and F...O, which are likely to be responsible for the packing of the molecules in a non‐centrosymmetric structure. Irradiation with blue light leads to the formation of Ru–ON (metastable state MS1) and Ru–η2‐(NO) (metastable state MS2) bond isomers, as shown by IR and UV–Vis spectroscopy. The structural features of the MS1 isomer were elucidated by photocrystallography. The complex exhibits exceptionally good thermal stability of the metastable state MS1, such that it can be populated by light at 290–300 K, which is important for potential applications. The second harmonic (SH) emission can be generated by femtosecond‐pulsed irradiation of the complex. The generated SH is rather efficient and stable under long‐term exposure. Finally, since both metastable states and harmonic generation can be generated at room temperature, an attempt to drive the SH response by photoisomerization of the nitrosyl ligand was made and is discussed. [ABSTRACT FROM AUTHOR]

An experimental measurement of the density of excited argon states 1s5, 1s4, 1s3, and 1s2 was carried out for an rf capacitive discharge in argon at a frequency of 13.56 MHz and 81 MHz for two pressures of 50 and 100 mTorr in a wide range of discharge applied power. A collision-radiative model was developed to calculate the densities of 1s states from the known electron density and the electron energy distribution function. The electron energy distribution function is obtained from a self-consistent discharge simulation based on the Particle in cell with Monte Carlo collisions model. It is shown that the calculated densities of the metastable states of argon are in good agreement with the experimentally measured ones. The calculated resonance state densities are underestimated. [ABSTRACT FROM AUTHOR]

• A tri-stimuli-responsive luminescent switching Pt(II) complexes was prepared. • The complex exhibits reversible vapoluminescent, themoluminescent and mechanoluminescent properties. • The mechanism of luminescent switching properties is clearly revealed. A square-planar bis(σ-acetylide) platinum(II) complex, Pt(PhenC CTES)(C C C 6 H 4 2 Cl) 2 (1) (PhenC CTES = 3-(2-triethylsilylethynyl)-1,10-phenanthroline) was synthesized. Three species with different stacking structures, including two solvated yellow-green samples 1· Cl 2 CHCHCl 2 and 1· ClCH 2 CH 2 Cl, and one red solvent-free species 1 , were obtained by exposure 1 into the different VOC vapors. 1· Cl 2 CHCHCl 2 and 1· ClCH 2 CH 2 Cl emit a green luminescence peaked at 513 (548, sh) nm and 545 (517, sh) nm, respectively and exhibit the vapor-, thermo-, and mechanical grinding triggered tri-stimuli-responsive luminescent switching properties. Once exposure to CH 2 Cl 2 vapor or heating at 110 °C, both 1· Cl 2 CHCHCl 2 and 1· ClCH 2 CH 2 Cl will lose their solvated molecule and converted to the red solvent-free species 1. Upon mechanical grinding, 1· Cl 2 CHCHCl 2 and 1· ClCH 2 CH 2 Cl will be changed to an amorphous species 1G with red color and red luminescence peaked at 675 nm. Meanwhile, the heating and ground samples could be converted back to the original crystalline 1· Cl 2 CHCHCl 2 and 1· ClCH 2 CH 2 Cl by absorbing Cl 2 CHCHCl 2 or ClCH 2 CH 2 Cl vapor. Systematic studies on the crystal structure, luminescence spectrum, PXRD patterns as well as TD-DFT calculations demonstrate that the mechanism of the reversible tri-stimuli-responsive luminescent switching properties of complex 1 is due to the interconversion of the lowest-energy excited states of metastable species between ligand to ligand/metal to ligand charge transfer (LLCT/MLCT) and ligand to ligand/metal-metal to ligand charge transfer (LLCT/MMLCT) caused by the formation/destruction of intermolecular Pt-Pt interactions and/or aromatic π-π stacking interactions under external stimuli. [Display omitted] [ABSTRACT FROM AUTHOR]

The paper presents an experimental and theoretical study of the radiative emission in the pure krypton lamp excited by dielectric barrier discharge. Parametric studies were made in the aim to observe the influence of the applied voltage, the gas pressure and the frequency on the radiation intensity emission from visible to infrared range. Stable dielectric barrier discharges were achieved between two identical insulated electrodes separated by 2 mm gap containing pure krypton at pressure from 129 to 460 mbar. The discharge was powered with a sinusoidal supply at frequencies from 10 to 50 kHz. Electrical characteristics of the DBD were studied. A spectroscopic and kinetic analysis of a pure krypton dielectric barrier discharge is reported here. The discharge emits radiations in UV, visible and IR range. In order to understand the emission process a theoretical interpretation of the results is given in the IR range by describing the chemical properties of the lamp. IR emission and a detailed study of kinetics allow to follow the population of metastable excited states of Krypton in (Kr*(3P0,2)). This population is indirectly responsible for UV emission. [ABSTRACT FROM AUTHOR]

Stabilisation technique is a traditional approach for studying resonances, such as the metastable autoionisation states. Stabilisation graphs are usually calculated by scaling the employed basis functions. Over the years, many methods for extracting the resonance complex energies from these graphs have been developed, nowadays, they are usually evaluated via analytical continuation schemes. However, many times it is difficult to obtain a well-behaved stabilisation graphs upon basis-set scaling. Herein, we illustrate that it is possible to shape stabilisation graphs to behave physically by adjusting the relevant Gaussian basis function exponents. We illustrate this for the excited Li–He and states [with He)], which serve as an excellent example since generating well-behaved graphs in this case is challenging. We show that by controlling and shaping the stabilisation graphs we can obtain converged complex energies, which are calculated by the resonances via Padé approach (a recently proposed analytical continuation scheme). Nevertheless, the concepts presented here are general to any stabilisation-graph based method. [ABSTRACT FROM AUTHOR]

Molecular excited vibrational states are metastable states and we incorporate their finite lifetimes into the theory of vibrational energy transfer between weakly interacting molecules, i.e., at internuclear distances at which they do not have a chemical bond. Expressions for the effective lifetime of an initially vibrationally excited molecule in the presence of a neighbouring molecule are derived in closed form. These expressions allow one to analyse the physics behind the energy transfer. It is shown that due to different finite lifetimes of the isolated excited molecules, a very efficient vibrational energy transfer can take place between them even if their energies are rather off-resonance. Examples are discussed. [ABSTRACT FROM AUTHOR]

Abstract The difficulty of building metastable vacua in string theory, has led some to conjecture that in the string theory landscape, potentials satisfy | ∇ V / V | ≥ c ∼ O (1). This condition, which is supported by different explicit constructions, suggests that the EFTs which lead to metastable de-Sitter vacua belong to what is dubbed as swampland. This condition endangers the paradigm of single field inflation. In this paper, we show how scalar excited initial states cannot rescue single field inflation from the swampland, as they produce large local scalar non-gaussianity, which is in conflict with the Planck upper bound. Instead, we demonstrate that one can salvage single field inflation using excited initial states for tensor perturbations, which in this case produce only large flattened non-gaussianity in the tensor bispectrum. We comment on the possible methods one can prepare such excited initial conditions for the tensor perturbations. [ABSTRACT FROM AUTHOR]

Layered van der Waals materials are emerging as compelling two-dimensional platforms for nanophotonics, polaritonics, valleytronics and spintronics, and have the potential to transform applications in sensing, imaging and quantum information processing. Among these, hexagonal boron nitride (hBN) is known to host ultra-bright, room-temperature quantum emitters, whose nature is yet to be fully understood. Here we present a set of measurements that give unique insight into the photophysical properties and level structure of hBN quantum emitters. Specifically, we report the existence of a class of hBN quantum emitters with a fastdecaying intermediate and a long-lived metastable state accessible from the first excited electronic state. Furthermore, by means of a two-laser repumping scheme, we show an enhanced photoluminescence and emission intensity, which can be utilized to realize a new modality of far-field super-resolution imaging. Our findings expand current understanding of quantum emitters in hBN and show new potential ways of harnessing their nonlinear optical properties in sub-diffraction nanoscopy. [ABSTRACT FROM AUTHOR]

Energy barriers for magnetization reversal of the finite-size Co chains on Pt(664) surface are calculated with taking the Dzyaloshinskii-Moriya interaction into account. For the numerical calculations the geodesic nudged elastic band method is employed. It has been found that the ground states of such atomic chains are noncollinear. The magnetization reversal of short atomic chains occurs without the formation of domain walls. At the same time, there are two nonequivalent ways for the magnetization reversal of longer atomic chains. The first way is the formation of clockwise domain wall (CDW) and the second way is the formation of anticlockwise domain wall (ACDW). The second way is energetically preferable. It is shown that a metastable state corresponding to the location of ACDW in the middle of the atomic chain can appear. The variation of the parameters of the Hamiltonian shows that the magnetization reversal via the CDW formation can occur only in a certain region of the parameters. The influence of the long-range dipole–dipole interaction on the energy barriers for the magnetization reversal is also investigated. It is shown that the most of the presented results can be satisfactory explained in the framework of the XY-model. The magnetic configurations of the atomic chain near the local minima and the saddle points can be approximated with simple analytical functions. [Display omitted] • Magnetization reversal of the finite-size Co chains on Pt(664) surface is studied. • The Dzyaloshinskii-Moriya interaction is taken into account. • The structures of the ground states and the excited states are investigated. • The energy barriers for the magnetization reversal are calculated. • Most of the results are explained in the framework of the XY-model. [ABSTRACT FROM AUTHOR]

We propose an excited-state molecular dynamics simulation method based on variational quantum algorithms at a computational cost comparable to that of ground-state simulations. We utilize the feature that excited-states can be obtained as metastable states in the restricted variational quantum eigensolver calculation with a hardware-efficient ansatz. To demonstrate the effectiveness of the method, molecular dynamics simulations are performed for the S1 excited-states of H 2 and CH 2 NH molecules. The results are consistent with those of the exact adiabatic simulations in the S1 states, except for the CH 2 NH system, after crossing the conical intersection, where the proposed method causes a nonadiabatic transition. [Display omitted] • An excited-state MD scheme based on variational quantum algorithms is presented. • Excited states can be obtained as metastable states by VQE calculations. • Excited-state MD simulations based on the VQE result in "diabatic" simulations. [ABSTRACT FROM AUTHOR]

Evaluated spectroscopic data and level schemes from radioactive decay and nuclear reaction studies are presented for 26 O, 26 F, 26 Ne, 26 Na, 26 Mg, 26 Al, 26 Si, 26 P, and 26 S. This evaluation for A = 26 supersedes the earlier one by P. M. Endt (1998En04) and updates for some nuclides in ENSDF. Highlights of this evaluation are the following: This evaluation includes search results for 26 S nuclide and its proton–decay mode (2011Fo08). An isomeric state (2.2 ms) in 26 F has been discovered by 2013Le03. The state is proposed at 643.4 keV 1 from γ –ray measurements. Internal-transition and beta-decay branches for the state are also determined. New excited levels in 26 Ne have been identified from 26 F β − decay (2.2 ms). For some 26 Si resonance states conflicting spin-parity assignments exist in the literature. These are identified by footnotes. 2015Do07 ( 3 He,n γ ) propose the first 0+ state above proton separation energy at an excitation energy of 5890 keV and suggested for additional independent measurements to confirm or refute the existence of 5946 keV 4 . 2016Ch09 consider 5946 keV level as a distinct excited state in their reanalysis of the literature data with possible spin-parity assignment of 0+ or 4+ This evaluation also includes discovery of an isomeric state, at 164.1 keV 1 , in 26 P by 2014NiZZ. [ABSTRACT FROM AUTHOR]

A metastable statesubjected to a couple of pulses transits to an excited levelof an atom with probabilitiesand, respectively. One photon is emitted in the transition from the levelto a lower atomic level. A second photon is emitted in the transition from the levelto a lowest atomic level. The first photon must be emitted before than the second one so they are both time ordered (time-bin) and entangled. It is calculated that the concurrence of the two produced time-bin photons as a function of,and the branching ratios of the two transitionsand (). It is found that the two produced photons are maximally entangled if the branching ratios are greater than 80%. It is also found that certain values of,and the branching ratios preclude entanglement between the two produced photons. Intervals of values forandwhere the concurrence is large enough and then two-qubit quantum information processing protocols can be optimally implemented are found. [ABSTRACT FROM AUTHOR]

On the light of a previous work and its recommendations by Matobaet al.[J. Phys. B41, 145205 (2008)], this paper proposes to look at the mobility of ground and metastable-excited states of C+ions moving into a helium buffer gas. The calculations, based on the three-temperature theory for solving the Boltzmann kinetic equation, are accomplished with quantum-mechanical transport cross sections at the low temperatures 4.3 and 77 K. The obtained mobility results are contrasted with the available theoretical data and experimental measurements, which show acceptable agreements. [ABSTRACT FROM PUBLISHER]

We present photoionization (PI) spectrum of ultracold ground state 85 RbCs molecules formed by spontaneous decay from J =1, v =8 rovibrational level of ( 2 ) Π 0 − 3 short range excited state molecules, which are produced from a space-adjustable dark spontaneous force optical trap. PI spectrum is obtained by scanning PI laser when photoassociation laser is locked by utilizing transfer cavity technique based on an ultrastable He–Ne laser as a reference laser. We calculated vibrational distribution of RbCs molecules in metastable ground state and corresponding transition probabilities to RbCs + ion in ( 1 ) Σ + 2 state. An enlarged PI spectrum with relative clear peaks is assigned to v =24–33 vibrational levels of molecular ion state. The method we used in PI spectrum analysis is also adoptable for other states of RbCs molecules or other kinds of molecules. [ABSTRACT FROM AUTHOR]

Excited states in the N = 102 isotones 166Gd and 164Sm have been observed following isomeric decay for the first time at RIBF, RIKEN. The half-lives of the isomeric states have been measured to be 950(60) and 600(140) ns for 166Gd and 164Sm, respectively. Based on the decay patterns and potential energy surface calculations, including β6 deformation, a spin and parity of 6- has been assigned to the isomeric states in both nuclei. Collective observables are discussed in light of the systematics of the region, giving insight into nuclear shape evolution. The decrease in the ground-band energies of 166Gd and 164Sm (N = 102) compared to 164Gd and 162Sm (N = 100), respectively, presents evidence for the predicted deformed shell closure at N = 100. [ABSTRACT FROM AUTHOR]