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Raman spectra of three natural carbonophosphates (sidorenkite, bonshtedtite, and bradleyite) with the general formula Na3MCO3PO4 (M is Mn, Fe, and Mg) were studied and compared. These spectra showed from 21 to 24 vibrational bands, of which the two most intense (964±5 and 1074±3 cm−1) correspond to the υ1(P–O) and υ1(C–O) modes. These two bands split into doublet peaks due to the occurrence of isomorphic impurities. It was found that the crystallographic orientation of the sample influences the intensity of most bands. Most bands assigned to the same vibrations showed a regular shift (the smallest in sidorenkite spectra, an intermediate in bonshtedtite, and the largest in bradleyite). We propose an algorithm that allows for diagnostics of carbonophosphates in inclusions by their Raman spectra, providing a reliable result even in the absence of energy-dispersive X-ray spectroscopy (EDX) data.

The use of illicit drugs across the world causes issues for users, healthcare workers and the public. Therefore, rapid and reliable onsite testing methods to detect these drugs are required. In this study, seven commercial surface-enhanced Raman spectroscopy (SERS) substrates A-G were compared for the analysis of cocaine. These substrates were compared using scanning electron microscopy to study the surface structure and Raman spectroscopy and to determine if there was any enhancement of the cocaine bands. Substrate B provided the best enhancement of known cocaine vibrational bands, allowing the detection down to concentrations of 1 ng/mL in standards and 10 ng/mL extracted from the oral fluid. The results showed that SERS is an ideal method for future rapid onsite analysis of illicit drugs in oral fluid. Commercial SERS substrates were compared for the analysis of cocaine. Substrate B provided the best result and was further tested with lower concentrations and extracts from the oral fluid. The application to oral fluid testing could prove useful for future onsite analysis.

Synthesized PEO:I2 complex composite films with different I2 concentrations were deposited onto fused silica substrates using a dip-coating method. Incorporation of PEO films with I2 increases the electrical conductivity of the composite, reaching a maximum of 46 mS/cm for 7 wt% I2. The optical and optoelectronic properties of the complex composite films were studied using the transmittance and reflectance spectra in the UV-Vis region. The transmittance of PEO decreases with increasing I2 content. From this study, the optical bandgap energy decreases from 4.42 to 3.28 eV as I2 content increases from 0 to 7 wt%. In addition, the refractive index for PEO films are in the range of 1.66 and 2.00.1H NMR spectra of pure PEO film shows two major peaks at 3.224 ppm and 1.038 ppm, with different widths assigned to the mobile polymer chains in the amorphous phase, whereas the broad component is assigned to the more rigid molecules in the crystalline phase, respectively. By adding I2 to the PEO, both peaks (amorphous and crystal) are shifted to lower NMR frequencies indicating that I2 is acting as a Lewis acid, and PEO is acting as Lewis base. Hence, molecular iodine reacts favorably with PEO molecules through a charge transfer mechanism, and the formation of triiodide ($${\mathrm{I}}_{3}^{-}$$ I 3 - ), the iodite ($${\mathrm{IO}}_{2}^{-}$$ IO 2 - ) anion, $${\mathrm{I}}_{2} \cdot \cdot \cdot \mathrm{ PEO}$$ I 2 · · · PEO and $${\mathrm{I}}_{2}^{+} \cdot \cdot \cdot \mathrm{ PEO}$$ I 2 + · · · PEO complexes. PEO:I2 complex composite films are expected to be suitable for optical, electrical, and optoelectronic applications.

Infrared spectra of five samples of sunflower seed oil and five samples of cold-pressed olive oil of different brands are recorded in the range of 650–3800 сm–1. The structural models of eight fatty acids (oleic, linoleic, palmitic, stearic, α-linolenic, arachidonic, eicosapentaenoic, and docosahexaenoic), as well as of triglycerides of the first four of these acids, are constructed using B3LYP/6-31G(d) methods. The vibrational wavenumbers and intensities in the IR spectra are calculated. The IR spectra of olive and sunflower seed oils are simulated using the supermolecular approach. The dependence of the intensity of vibrational bands at νexp = 914 and 3009 сm–1 on the concentration of triglycerides of oleic and linoleic acids in oils, as well as on the saturation degree of fatty acids, are studied. Experimental and empirical dependences are plotted to estimate the relative concentrations of triglycerides of oleic and linoleic acids in mixtures of olive and sunflower seed oils. The applicability of the density functional theory in combination with IR spectroscopy for characterization of vegetable oils is discussed.

In anthropological analysis of burned bone, the presence of a white heat line (WHL) aids in determining a bone’s physical condition prior to burning, distinguishing between those burned fleshed or wet versus dry, making this thermal signature an important source of information regarding the relative timing of burning. While the relationship between WHLs and a bone’s physical condition has been studied, there is a lack of research concerning WHL chemical composition. The present study assessed the composition of WHLs that form on burned bone using Fourier Transform Infrared Spectroscopy (FTIR), including the effects of soft tissue and retention of bone’s organic material on a WHL’s development and appearance. Experimental remains consisted of isolated bones from pig (Sus scrofa), sheep (Ovis aries), white-tailed deer (Odocoileus virginianus), and elk (Cervus elaphus) in five physical conditions: fleshed, defleshed/very wet, partially wet, dry, and dry/soaked. Chemical composition was analyzed using spectral peak heights of the carbonate (CO3) ν3 (1415 cm-1), phosphate (PO4) ν3 (1035 cm-1), and amide I (1660 cm-1) vibrational bands. WHLs formed on 8 of 16 bones burned fleshed (50%) compared to 8 of 27 defleshed/very wet (29.6%). The partially wet, dry, and dry/soaked sample groups did not develop a WHL. Results indicate WHLs that formed on fleshed bone contained an increased amount of CO3, PO4, and amide I versus unburned controls. In contrast, WHLs that formed on defleshed/very wet bone contained decreased amounts. Additional research is needed to explore the exact mechanisms causing the formation of WHLs and their physical appearance.

Non-yrast, excited states in neutron-rich $^{186}$W were populated via inelastic-scattering reactions using beams of $^{136}$Xe nuclei accelerated to 725 and 800 MeV. Levels populated in the reactions were investigated via particle-$ \gamma $ coincidence techniques using the Gammasphere array of High-Purity Germanium detectors and the compact heavy-ion counter, CHICO2. The $ K^{\pi} = 2 ^{+} $ ($\gamma$), $ K^{\pi} = 0^{+}$ and $ K^{\pi} = 2^{-} $ (octupole) rotational side bands were extended to spins $ 14\hbar $, $ 12\hbar $, and $ 13\hbar $, respectively. A staggering pattern observed in the energies of levels in the $ K^{\pi} = 2^{+} $ band was found to be consistent with a potential that gets softer to vibration in the $ \gamma $ degree of freedom with increasing spin. The odd-even staggering of states in the $ K^{\pi} = 2^{-}$ band was found to exhibit a phase opposite to that seen in the $ \gamma $ band; an effect most probably associated with Coriolis coupling to other, unobserved octupole vibrational bands in $^{186}$W., Comment: 14 pages, 16 figures

We resolve the dispersion of multiple vibro-polariton modes issued from the coupling of several vibrational bands of the methylene group with a resonant modes of a mid-infrared micro-cavity. The experimental results are in excellent agreement with numerical simulations.

Extensive infrared spectra of the weakly-bound CO₂-CO dimer are observed in the carbon dioxide ν₃ asymmetric stretch region (≈2350 cm⁻¹) using a tunable infrared OPO laser source to probe a pulsed slit jet supersonic expansion. Both C-bonded and O-bonded isomers are analysed for the normal isotopologue as well as for ¹³CO₂-CO and ¹⁶O¹³C¹⁸O-CO, the latter being the first observation of an asymmetrically substituted form for which all values of Ka are allowed. Combination bands involving the lowest in-plane intermolecular bending modes are also studied for both isomers. Weak bands near 2337 cm⁻¹ are assigned to CO₂ hot band transitions (v1, vˡ²₂, v₃) = (01¹1) ← (01¹0), yielding the splitting of the degenerate CO₂ ν₂ bend into in-plane and out-of-plane components due to the presence of the CO. This splitting has rather different values for the C- and O- bonded isomers, 4.57 and 1.59 cm⁻¹, respectively, with the out-of-plane mode higher in energy than the in-plane for both cases.

Cyclic water clusters are pivotal for understanding atmospheric reactions as well as liquid water, yet the temperature (T) dependence of their dynamics and spectroscopy is poorly studied. The devel...

The electronic structure of the (3,5-dimethylpyrazole-N2)(N-salicylidenephenyl-alaninato-O,N,O′)copper(II) complex and its ethanol adduct is calculated theoretically using different approaches. A comparison with X-ray data shows that M06/SVP and LC-BLYP/TZVP methods give the best theoretical geometry. The vibrational bands in the range 100–500 cm−1 are assigned by the aid of the Chemcraft software. Unrelaxed potential energy curves of the interaction of ethanol with our compound are obtained and examined.

This article presents the synthesis of Au/Li nanoparticles through green synthesis approximation, using extract from Opuntia ficus indica (OFI). The TEM images show the efficiency of this method for the synthesis of nanoparticles. The vibrational properties of Au/Li nanoparticles were analyzed through Raman spectroscopy. The results of the analysis show two vibrational bands around 93 cm−1and 242 cm−1. Furthermore, the article presents a theoretical study of clusters AumLikin which obtained minimum energy structures were obtained and predicted the normal modes of vibration in the Raman spectrum of each one of the clusters AumLik. We observed a theoretical and experimental behavior in the optical and the vibrational properties.

Several significant improvements are proposed to the computational molecular spectroscopy protocol MARVEL (Measured Active Rotational-Vibrational Energy Levels) facilitating the inversion of a large set of measured rovibrational transitions to energy levels. The most important algorithmic changes include the use of groups of transitions, blocked by their estimated experimental (source segment) uncertainties, an inversion and weighted least-squares refinement procedure based on sequential addition of blocks of decreasing accuracy, the introduction of spectroscopic cycles into the refinement process, automated recalibration, synchronization of the combination difference relations to reduce residual uncertainties in the resulting dataset of empirical (MARVEL) energy levels, and improved classification of the lines and energy levels based on their accuracy and dependability. The resulting protocol, through handling a large number of measurements of similar accuracy, retains, or even improves upon, the best reported uncertainties of the spectroscopic transitions employed. To show its advantages, the extended MARVEL protocol is applied for the analysis of the complete set of highly accurate H216O transition measurements. As a result, almost 300 highly accurate energy levels of H216O are reported in the energy range of 0-6000 cm-1. Out of the 15 vibrational bands involved in accurately measured rovibrational transitions, the following three have definitely highly accurate empirical rovibrational energies of 8-10 digits of accuracy: (v1v2v3) = (0 0 0), (0 1 0), and (0 2 0), where v1, v2, and v3 stand for the symmetric stretch, bend, and antisymmetric stretch vibrational quantum numbers. The dataset of experimental rovibrational transitions and empirical rovibrational energy levels assembled during this study, both with improved uncertainties, is considerably larger and more accurate than the best previous datasets.

The 1+1 REMPI spectrum of SiO in the 210–220 nm range was recorded. Observed bands were mostly assigned to the vibrational bands v ″ = 0 - 3 , v ′ = 5 - 10 of the A - X electronic transition. Additionally, a band near 216–217 nm was tentatively assigned as a 2-photon transition from X to the n = 12 , 13 [ X 2 Σ + , v + = 1 ] Rydberg states. Based on observed lines we estimated the IP of SiO to be 11.594(5) eV. The SiO+ cation has previously been identified as having a cycling transition useful for state control by optical pumping. Our work allowed us to identify an efficient method for loading an ion trap with rotationally and vibrationally cold SiO+ from an ablated sample of SiO by photoionizing through the (5,0) A - X band at 213.977 nm.

International audience; Temperature dependence of polarized infrared (IR) reflectance spectra of two-dimensional weakly dimerized organic conductor δ-(BEDT-TTF)4[2,6-anthracene-bis(sulfonate)]·4H2O with 14-filled band has been measured to investigate the metal-insulator phase transition at TMI=85K linked to charge ordering (CO). Vibrational bands related to C=C stretching vibrations of the BEDT-TTF donor molecule give evidence of the CO and charge fluctuations both in the metallic and insulating phases above and below 85 K, respectively. Considerable modifications of the vibrational features due to electron-molecular vibration coupling are also observed. The phase transition is associated with the reorganization of hydrogen OH»O bonds in anion layers between the sulfonate moieties of the anion and the trapped water molecules, which is transmitted to conducting BEDT-TTF layers through weaker C-H»O bonds. The analysis of electronic bands confirms the presence of strong electronic correlations in the material. Two electronic absorptions are observed in the mid-IR region, attributed to transitions between Hubbard bands and transitions inside BEDT-TTF dimers. A low-energy electronic absorption in the far-IR region is attributed to collective excitations of the short-range charge order. Below 85 K, the opening of a charge gap of ∼24 meV is observed both parallel and perpendicular to the BEDT-TTF stacking direction. The spectroscopic data indicate that the CO phase transition is a consequence of both Coulomb interactions between charge carriers and donor-acceptor interactions. © 2021 American Physical Society.

A green ancient thread sample from a Chilean mummy turban was analyzed by plasmon-enhanced Raman scattering spectroscopy using a direct drop-colloidal method. The enhanced-Raman signals in the sample are associated with biomolecules from the thread and two coexisting dyes, indigo and leuco-indigo. The presence of indigo (blue colour) was identified from its most characteristic vibrational bands. Leuco-indigo (yellow colour) was identified for the first time in an ancient textile; its SERS signals are coincident with the SERS bands of a synthesized leuco-indigo. The interconversion leuco-indigo to indigo was followed by UV-visible spectroscopy. Based on theoretical calculations it is proposed that the interconversion involves a π electron delocalization mainly around the NC-CN bridge. The mixture of both dyes (indigo and leuco-indigo) is the responsible for the green colour observed.

The 2-butyn-1-yl radical is an isomer of C4H5 and is structurally similar to the propargyl radical, which is the simplest resonance-stabilized hydrocarbon radical. The C4H5 radical is likely to be important to astrochemistry and combustion, similar to propargyl, yet little research has been done on its spectroscopic properties. In this work, seven vibrational bands of the 2-butyn-1-yl radical are reported. The radical was formed by pyrolysis of 1-bromo-2-butyne at 800 K and isolated in a low-temperature argon matrix. The experimentally observed frequencies and intensities of the seven vibrational bands were found to be consistent with QCISD predictions from the literature and with new B3LYP calculations in this work.

Rotational structures have been measured using the Jurogam II and GAMMASPHERE arrays at low spin following the Gd155(α,2n)Dy157 and Nd148(C12,5n)Dy155 reactions at 25 and 65 MeV, respectively. We report high-K bands, which are conjectured to be the first candidates of a Kπ=2+γ vibrational band, built on the [505]11/2− neutron orbital, in both odd-ADy155,157 isotopes. The coupling of the first excited K=0+ states or the so-called β vibrational bands at 661 and 676 keV in Dy154 and Dy156 to the [505]11/2− orbital, to produce a Kπ=11/2− band, was not observed in both Dy155 and Dy157, respectively. The implication of these findings on the interpretation of the first excited 0+ states in the core nuclei Dy154 and Dy156 are also discussed.

In situ FTIR spectroscopy in combination with results from DFT calculations was used to determine the composition of mixed-metal clusters {CexZr6-x(μ3-O)4(μ3-OH)4} in Ce/Zr-UiO-66 compounds. Detailed, quantitative evaluation of vibrational bands ν(OH) of (μ3-OH)CexZr3-x groups allowed us to distinguish between two possible models: a solid solution or the presence of distinct clusters. This relatively straightfoward method should be also transferable to other mixed-metal metal-organic frameworks (MOFs).

An analysis is presented for the vacuum ultraviolet C2N2 C1Bu ← X1Σg+ transition. Contrary to previous assumptions this is found to be a linear to bent transition with a trans-bent C1Bu excited electronic state. The band origin is at 59 840 cm–1. Vibrational bands between 170 and 145 nm are assigned. Vibrational frequencies for the C1Bu state are found to be ν1 = 2055 ± 20 cm–1 for the symmetric CN stretch, ν2 = 979 ± 20 cm–1 for the symmetric CC stretch, ν3 = 542 ± 10 cm–1 for the trans-bend, ν4 = 131 ± 10 cm–1 for the out-of-plane torsional bend, and ν6 = 141 ± 10 cm–1 for the cis-bend.

The Raman spectra of five samples of sunflower seed oil and five samples of cold-pressed olive oil of various brands are recorded in the range of 500–2000 cm–1. Within the framework of the B3LYP/6-31G(d)/6-31G(d,p)/6-31+G(d,p)/6-311G(d)/6-311G(d, p)/6-311+G(d,p) methods, the structural models of eight fatty acids (oleic, linoleic, palmitic, stearic, α-linolenic, arachidonic, eicosapentaenoic, and docosahexaenoic) are constructed, and also within the framework of the B3LYP/6-31G(d) method, the structural models of triglycerides of the first four of the above acids are obtained. The vibrational wavenumbers and intensities in the IR and Raman spectra are calculated. The Raman spectra of olive oil and sunflower seed oil were simulated by using the supermolecular approach. We investigated the dependence of the relative intensity of the vibrational bands νexp = 1660 and 1445 cm–1 on the concentration of triglycerides in oils of oleic and linoleic acids and the dependence of the intensity of these bands on the degree of saturation of fatty acids. Experimental and empirical dependences are constructed to estimate the relative concentration of triglycerides of oleic and linoleic acids in a mixture of olive oil and sunflower seed oil. The applicability of the density functional theory together with the vibrational spectroscopy for the identification of mixtures of vegetable oils is discussed.

The dependence of the intermolecular interaction potentials on the vibrational quantum numbers of the H2O molecule is derived for the H2O–Ne, H2O–Kr, and H2O–Xe systems. The broadening γ and shift δ coefficients are calculated for seven vibrational bands ν1, ν2, ν3, 2ν2, ν1 + ν2, ν2 + ν3, and ν1 + ν2 + ν3 of the H2O molecule from the absorption region 640–9550 cm−1. An analytical formula is suggested for calculation of the broadening coefficients γ at T = 296 K. It is shown that the excitation of stretching modes of the vibrations in the H2O molecule increases the broadening coefficients. The influence of the bending vibrations on γ is insignificant.

We compare the intensities of purely rotational and ro-vibrational transitions within the ground electronic state of CO calculated with two dipole moment functions (DMFs) of Li et al. (2015) and four potential energy functions (PEFs), a semi-empirical PEF of Meshkov et al. (doi: https://doi.org//10.5281/zenodo.1198744) and three empirical ones due to Coxon and Hajigeorgiou (2004, 2016, 2017). All these PEFs reproduce the experimental line positions with similar normalized standard deviations (NSDs), and the energy mismatch between the vibrational levels with v ⩽ 5 does not exceed 0.0002 cm−1 among all PEFs. Despite these similarities, we find that the rotational anomalies in the 0-0, 1-1, 2-2, 3-3, 4-4, and 5-0 bands shown in Figs. 3 and 4 of Medvedev et al. (2017) change their intensities by a factor of 2 to 250 among the above PEFs at a given DMF. Both the positions and intensities of the anomalies change between two DMFs at a given PEF.

A virgin sample of pure polyvinyl alcohol (PVA) in combination with other polymeric samples containing pre-calculated amounts of lepidium sativum natural plant seed extract was successfully prepared. Structural modification was investigated through a combination of both Fourier transformation infrared (FT-IR) combined with X-ray diffraction (XRD). Both techniques indicate interaction and complexation of the polymeric matrix through changes in vibrational bands at 1331 and 849 cm−1 owing to the CH2 wagging vibration and carbon stretching vibrations respectively. EDAX analysis supported with atomic absorption experimental data were used to investigate the structure and type of elements present in the natural seeds. Obtained data explain the complexation process between the polymeric material and plant extract attributed to the presence of Fe+2 ions even in ppm level.

Unintentionally doped cubic boron nitride (cBN) single crystals with color zoning were investigated by Raman spectroscopy. Besides the TO mode at 1053 cm−1 and the LO mode at 1304 cm−1, some little vibrational bands at 925 cm−1, 955 cm−1and 1247 cm−1 corresponding to the amber regions in the { 1 ¯ 1 ¯ 1 ¯ } N sectors of cBN crystals were observed. These vibrational bands probably result from the disorder-activated Raman scattering (DARS) due to the high defect densities. It is shown that these defects and impurities are nonuniform, easily formed and incorporated in { 1 ¯ 1 ¯ 1 ¯ } N growth sectors during the growth process of cBN crystals. These defects and impurities are color centers in cBN, therefore, the cBN crystal exhibits symmetrical color zoning relative to the {111} growth sectors.

The Raman spectra of pure H-2 and CH4 gases and their 5 gaseous mixtures were collected at pressures from 1 to 40MPa at ambient temperature. They were systematically analyzed in order to establish methodology for quantitative determination of composition and pressure of H2CH4 bearing fluid inclusions. The peak positions of 4 vibrational bands of H-2 in pure H-2 gas decrease first and then increase after reaching their minima values at about 30MPa. The wavenumbers of ?(1) band of CH4 in pure CH4 gas decreases in wavenumber monotonically in the entire investigated pressure range. In H2CH4 gaseous mixtures, both the peak positions of H-2 and CH4 shift to lower wavenumbers with increasing pressure. The peak positions of ?(1) band of CH4 can be used to determine the pressure of pure CH4 and CH4-dominated fluids, where the peak position shifts are sufficiently large for precise pressure determination. The peak widths of H-2 and CH4 in pure H-2 and CH4 gases and H2CH4 gaseous mixtures broaden as pressure increases. The peak area ratios and the peak height ratios between CH4 and H-2 in H2CH4 binary mixtures are sensitive to composition (i.e., molar ratio between CH4 and H-2) but are almost independent of pressure. Thus, the peak area or peak height ratios can be used to determine the composition of H2CH4 fluids. On the other hand, the peak height ratios of Q(1)(1) to Q(1)(3) bands in pure H-2 gas or H-2-dominated gaseous mixtures are sensitive to pressure and insensitive to composition. Therefore, in H-2-dominated fluids, the relative peak heights of Q(1)(1) and Q(1)(3) of H-2 is a better alternative for pressure determination. Based on our established Raman quantitative analysis method, we determined the composition and internal pressure of a natural H2CH4-bearing melt inclusion in quartz from Jiajika granite.

In this study, a surface-enhanced Raman scattering (SERS) spectroscopic approach was developed for a trace-level detection of procainamide in an aqueous medium. Silver-based nanoparticles as active substrates were synthesized using the reduction technique in presence of a citrate stabilizer and were characterized with UV–Vis, FT-IR, and FE-SEM techniques. The SERS spectra of procainamide were collected at a wide concentration range. The vibrational bands and frequency shifts associated with the enhanced Raman signals were identified, analyzed, and assigned to respective active modes. First-principle calculations were performed to elaborate on potential substrate-drug interaction possibilities and energies at the molecular level. The intensity enhancements observed for selected SERS peaks, namely at 1246 cm−1, 1370 cm−1, 1613 cm−1 and 1661 cm−1, were further utilized for the development of a consistent and fast quantification of procainamide. The developed approach displayed an excellent sensitivity and good reproducibility. The detection limit for procainamide was successfully attained at the level of one-tenth of nanomolar concentrations corresponding to a coefficient of regression (R2) of 0.9998. The obtained results revealed that this method is promising for drug and medical applications.

From γ-γ-γ and γ-γ-γ-γ coincidence studies of spontaneous fission of 252Cf, new high spin states in 148Ce were identified. The octupole bands with s = + 1 and s = − 1 are expanded with spins with 28+ and 18−, respectively. Importantly, a 1γ vibrational band has been established up to 14+ and a 1β vibrational band up to 6+. The levels in γ and β bands in 148Ce are compared systematically to those in neighboring 150Nd and 152Sm isotones. This comparison informs the role of deformation and shape transition in this mass region. New 3− and 5− members of the s = + 1 octupole band were observed.

In this work, a full factorial design 23 for the optimization of experiments was performed using a portable Raman spectrometer to find ideal instrumental conditions (laser power, analysis accessory, and luminosity) in the detection and quantification of adulterant, soybean oil, in extra virgin olive oil (EVOO). The ratio between the intensities of vibrational bands of 1440 and 1266 cm–1, characteristics of oleic and linoleic acids, respectively, were evaluated as a response measure. It was found that the configuration of the accessories has no significant influence on the analytical response. For quantification of soybean oil in EVOO, an analytical curve was constructed with six concentrations of the binary mixture containing EVOO with soybean oil (100/0; 80/20; 60/40; 40/60; 20/80; and 0/100 % v/v) and the model was validated from use of five samples adulterated with known concentrations (90/10; 70/30; 50/50; 30/70; and 10/90 % v/v) employing the intensity (I) ratio of the I1266/I1440 and I1656/I1440. The best regression method, using ordinary least squares (OLS), was through the ratio of the intensity of I1266/I1440, which presented higher linearity with R2c and R²p of 0.9769 and 0.9450, respectively; and Root Mean Square Error of Calibration (RMSEC) and Root Mean Square Error of Prediction (RMSEP) of 1.445 and 1.975 % (v/v), respectively.

Extensive infrared spectra of the weakly-bound CO2-CO dimer are observed in the carbon dioxide ν3 asymmetric stretch region (≈2350 cm−1) using a tunable infrared OPO laser source to probe a pulsed ...

The present work reports the detailed molecular, structural and spectral studies including DFT, FTIR, FT-Raman, NMR, UV Vis. spectrum of a bimetallic salt, [Ni(L)][CoCl 4 ] where L = 3,7- bis (2-aminoethyl)-1,3,5,7-tetraazabicyclo(3.3.1)nonane using DFT/TD-DFT calculations, FTIR, FT-Raman, NMR and UV Vis. spectra. The bimetallic salt, [Ni(L)][CoCl 4 ] was found to crystallize in the space group P1 with unit cell dimensions a = 7.1740(15), b = 8.1583(16) and c = 8.3102(16) A as reported elsewhere. The molecular structure, IR and NMR ( 13 C and 1 H) spectra of the bimetallic salt were interpreted by comparing the experimental results with the theoretical one using B3LYP/6–31G(d,p) calculations. The vibrational bands appearing in the FTIR and FT-Raman are assigned using animated modes. Molecular properties like HOMO–LUMO analysis, non-linear optical properties, atomic charges and thermodynamic properties have also been studied at the same level of theory. The theoretical results are found in good correlation with the experimental data. Moreover, the Hirshfeld analysis was carried out to ascertain the secondary interactions and associated 2D fingerprint plots.