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FT-IR and FT-Raman spectrum of 1-butyl-2-(4-hydroxyphenyl)-4,5-dimethyl-imidazole 3-oxide were recorded and theoretical study has been made using Gaussian09 software package. DFT/B3LYP calculations have been done using 6-311++G (d, p) (5D, 7F) basis sets to investigate the vibrational frequencies and geometrical parameters. The assignments of the normal modes are done by potential energy distribution (PED) calculations. First and second hyperpolarizabilities are calculated in order to find its role in non-linear optics. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. Molecular Electrostatic Potential was calculated by the DFT method and predicts the most reactive part in the molecule. The calculated NMR values are in good agreement with experimental data. Reactive sites of the title molecule have been determined by calculations of average local ionization surfaces and Fukui functions. Analyzing electron density between atoms, intra-molecular non-covalent interactions have been determined. Possible locations prone to autoxidation and locations where degradation could start have been determined by calculation of bond dissociation energies for all single acyclic bonds. Atoms with pronounced interactions with water molecules have been located by calculations of radial distribution functions, obtained after molecular dynamics simulations. The docked title compound forms a stable complex with CDK inhibitor and gives a binding affinity value of −6.3 kcal/mol and the results suggest that the compound might exhibit inhibitory activity against CDK inhibitor.

FT-IR and FT-Raman spectra of 1-hydroxy-4,5,8-tris(4-methoxyphenyl)anthraquinone were recorded and analyzed. The vibrational wavenumbers were computed using DFT quantum chemical calculations. The data obtained from wavenumber calculations were used to assign the vibrational bands obtained experimentally. A detailed molecular picture of the title compound and its interactions were obtained from NBO analysis. From the MEP plot it is clear that the negative electrostatic potential regions are mainly localized over carbonyl group. There is some evidence of a region of negative electrostatic potential due to π-electron density of the benzo groups. Molecular docking study shows that methoxy groups attached to the phenyl rings and hydroxyl group are crucial for binding and the title compound might exhibit inhibitory activity against PI3K and may act as an anti-neoplastic agent.

FT-IR spectrum of 3-Methyl-4{(E)-[4-(methylsulfanyl)-benzylidenelamino}1H-1,2,4-triazole-5(4H)-thi one was recorded and analysed. The vibrational wavenumbers were computed and at HF and DFT levels of theory. The data obtained from wavenumber calculations are used to assign the vibrational bands obtained in the IR spectrum. The NH stretching wavenumber is red shifted in the IR spectrum from the computed value, which indicates the weakening of the NH bond. The geometrical parameters of the title compound are in agreement with the XRD results. NBO analysis, HOMO-LUMO, first and second order hyperpolarizability and molecular electrostatic potential results are also reported. From the MEP map it is evident that the negative regions are localized over the sulphur atoms and N-3 atom of triazole ring and the maximum positive region is localized on NH group, indicating a possible site for nucleophilic attack. Prediction of Activity Spectra analysis of the title compound predicts anti-tuberculostic activity with probability to be active value of 0.543. Molecular docking studies reveal that the triazole nitrogen atoms and the thione sulphur atom play vital role in bonding and results draw us to the conclusion that the compound might exhibit anti-tuberculostic activity. (C) 2015 Elsevier B.V. All rights reserved.

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 2-[(E)-2-(2-bromophenyl)ethenyl]quinoline-6-carboxylic acid have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of the normal modes of vibrations was done using GAR2PED program. H-1 NMR chemical shifts calculations were carried out by using B3LYP functional with SDD basis set. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. MEP was performed by the DFT method and the predicted infrared intensities and Raman activities have also been reported. The calculated geometrical parameters are in agreement with that of similar derivatives. The title compound forms a stable complex with PknB as is evident from the binding affinity values and the molecular docking results suggest that the compound might exhibit inhibitory activity against PknB and this may result in development of new anti-tuberculostic agents. (C) 2015 Elsevier B.V. All rights reserved.

FT-IR spectrum of (2E)-3-(3-nitrophenyl)-1-[4-piperidin-1-yl]prop-2-en-1-one was recorded and analyzed. The vibrational wavenumbers were computed using HF and DFT quantum chemical calculations. The data obtained from wavenumber calculations are used to assign JR bands. Potential energy distribution was done using GAR2PED software. The geometrical parameters of the title compound are in agreement with the XRD results. NBO analysis, HOMO LUMO, first and second hyperpolarizability and molecular electrostatic potential results are also reported. The possible electrophile attacking sites of the title molecule is identified using MEP surface plot study. Molecular docking results predicted the anti-leishmanic activity for the compound. (C) 2015 Published by Elsevier B.V.

We report the preparation and results of vibrational spectral analysis, which were obtained using both FT-IR and FT-Raman spectroscopy, for three 1-alkyl-1-methylpiperazine-1,4-diium salts (AMPSs), where alkyl is benzyl 4a, n-octadecyl 4b, and methyl 4c, respectively. These were prepared by multistep synthesis from piperazine. The acid base study of AMPSs was performed and corresponding acid base constants were obtained. Single crystals of AMPSs suitable for XRD-analysis were obtained and analyzed. The complete vibrational assignments of wavenumbers were made on the basis of a potential energy distribution. The HOMO and LUMO analysis was used to determine the charge transfer within the molecules. The calculated first hyperpolarizabilities of AMPSs 4a-4c are 48.34, 57.77 and 123.41 times that of urea. As can be seen from the MEP plots, the negative electrostatic potential regions are mainly localized over the chlorine and oxygen atoms for compounds 4a and 4b and chlorine and iodine atoms of compound 4c, and are possible sites for electrophilic attack. (C) 2015 Elsevier B.V. All rights reserved.

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 5-tert-Butyl-6-chloro-N-[(4-(trifluoromethyl)phenyl]Pyrazine-2-carboxamide have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of normal modes of vibrations was done using GAR2PED program. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. From the NBO analysis it is evident that the increased electron density at the nitrogen, carbon atoms leads to the elongation of respective bond length and a lowering of the corresponding stretching wave number. The calculated geometrical parameters are in agreement with that of similar derivatives. The calculated first hyperpolarizability is high and the calculated data suggest an extended sr-electron delocalization over the pyrazine ring and carboxamide moiety which is responsible for the nonlinearity of the molecule. (c) 2014 Elsevier B.V. All rights reserved.

Quinoline derivatives have good nonlinear optical properties and have been extensively studied due to their great potential application in the field of organic light emitting diodes. Quantum chemical calculations of the equilibrium geometry, harmonic vibrational frequencies, infrared intensities and Raman activities of 4-hydroxy-2-oxo-1,2-dihydroquinoline-7-carboxylic acid in the ground state were reported. Potential energy distribution of normal modes of vibrations was done using GAR2PED program. The synthesis, H-1 NMR and PES scan results are also discussed. Nonlinear optical behavior of the examined molecule was investigated by the determination of first hyperpolarizability. The calculated HOMO and LUMO energies show the chemical activity of the molecule. The stability of the molecule arising from hyperconjugative interaction and charge delocalization has been analyzed using NBO analysis. The calculated geometrical parameters are in agreement with that of similar derivatives. (C) 2013 Elsevier B.V. All rights reserved.

Anthraquinone derivatives are most important class of a system that absorb in the visible region. In this work, the vibrational spectral analysis was carried out using FT-IR and FT-Raman spectroscopy for 2,4-bis(2-methoxyphenyl)-1-phenylanthracene-9,10-dione. Theoretical calculations were performed by ab initio HF and OFT methods using 6-31G. basis set. The complete vibrational assignments of wavenumbers were made on the basis of potential energy distribution. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The calculated geometrical parameters (DFT) are in agreement with that of similar derivatives. The calculated first hyperpolarizability of the title compound is 4.69 x 10(-30) esu, which is 36.08 times that of urea and the title compound and the series of compounds it represents are attractive candidates for further studies in non linear optical applications. (C) 2013 Elsevier B.V. All rights reserved.

The synthesis and antimicrobial properties of 5-[(4-Bromophenyl)acetamido]-2-(4-tertbutylphenyl) benzoxazole are reported in the present work. The optimized molecular structure, 1 H NMR, vibrational frequencies, corresponding vibrational assignments of 5-[(4-Bromophenyl)acetamido]-2-(4-tert-butylphenyl) benzoxazole have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of the normal modes of vibrations was done using GAR2PED program. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. MEP was performed by the SDD method and the predicted infrared intensities have also been reported. The calculated geometrical parameters are in agreement with that of similar derivates. The first hyperpolarizability is high and the title compound is suitable for further NLO studies. Microbiological results indicated that the title compound possessed a broad spectrum activity against the tested Gram-positive, Gram-negative bacteria.

The IR and Raman spectra of the title compound have been recorded and analyzed. The harmonic vibrational wavenumbers were calculated theoretically using Gaussian09 software package. Wavenumbers were calculated at HF and DFT levels. The observed wavenumbers were found to be in agreement with the calculated (DFT) values. The small differences between experimental and calculated vibrational modes are observed. It must be due to the fact that experimental results belong to solid phase and theoretical calculations belong to gaseous phase. The first hyperpolarizability, infrared intensities and Raman activities are reported.

The IR and Raman spectra of the title compound have been recorded and analyzed. The harmonic vibrational wavenumbers were calculated theoretically using Gaussian09 software package. Calculations were performed by HF and DFT levels using the standard 6-31G* basis sets. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands found in the IR and Raman spectra of the title compound. The calculated wavenumbers (DFT) agree well with the observed wavenumbers. The predicted infrared intensities, Raman activities and first hyperpolarizability are reported.

The IR and Raman spectra of 4-chloro-3-methylphenol have been recorded and analyzed. The harmonic vibrational wavenumbers were calculated using Gaussian09 software. Calculations were performed by HF and DFT levels using the standard 6-31G* basis. The calculated wavenumbers (DFT) agree well with the observed wavenumbers. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands found in the IR and Raman spectra of the title compound. The predicted infrared intensities, Raman activities and first hyperpolarizabilty are reported.

In the present work, we reported the combined experimental and theoretical study on the vibrational spectra of p-Acetylbenzonitrile. Calculations were performed by HF and DFT levels using the standard 6-31G* basis sets. The calculated wavenumbers (DFT) agree well with the observed wavenumbers. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands found in the IR and Raman spectra of the title compound. The predicted infrared intensities, Raman activities and first hyperpolarizability are reported.From the HOMO and LUMO analysis, The hardness value of the title compound is 1.879 eV and the title compound belongs to hard material.

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 5-nitro-2-(4-nitrobenzyl) benzoxazole have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of the normal modes of vibrations was done using GAR2PED program. The energy and oscillator strength calculated by time dependent density functional theory almost compliments with experimental findings. Gauge-including atomic orbital H-1 NMR chemical shifts calculations were carried out by using B3LYP functional with 6-31G(*) basis set. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization have been analyzed using NBO analysis. MEP was performed by the DFT method and the predicted infrared intensities and Raman activities have also been reported. The calculated geometrical parameters are in agreement with that of similar derivatives. (C) 2012 Elsevier B.V. All rights reserved.

FTIR and FT-Raman spectrum of 1-chloro-2-methyl-2-phenylpropane were recorded and analyzed. The vibrational wavenumbers were examined theoretically using the Gaussian03 set of quantum chemistry codes. The experimental frequencies are in agreement with the calculated (B3LYP) scaled values. The predicted infrared intensities, Raman activities and first hyperpolarizability are reported.

The FTIR and FT-Raman spectra of 1-chloroethylbenzene were recorded and analyzed. The harmonic vibrational wavaenumbers were calculated theoretically using Gaussian03 set of quantum chemistry codes. The calculated wavenumbers (B3LYP) agree well with the observed wavenumbers. The calculated first hyperpolarizability is reported and the title compound is an attractive object for further studies of nonlinear optics.

FTIR and FT-Raman spectrum of 5,-benzo-1,3-benzodioxole were recorded and analyzed. The vibrational wavenumbers were examined theoretically using the Gaussian03 set of quantum chemistry codes. The experimental frequencies are in agreement with the calculated (B3LYP) scaled values. The predicted infrared intensities and Raman activities are reported.

The IR and Raman spectra of 4-nitropyrocatechol have been recorded and analyzed. The harmonic vibrational wavenumbers were calculated theoretically using Gaussian03 software. Calculations were performed by the DFT level using the standard 6-31G* basis. The calculated wavenumbers agree well with the observed wavenumbers. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands found in the IR and Raman spectra of the title compound. The predicted infrared intensities and Raman activities are reported.

FTIR and FT-Raman spectrum of 5,6-benzo-2-pyrone were recorded and analyzed. The vibrational wavenumbers were examined theoretically using the Gaussian03 set of quantum chemistry codes. The experimental frequencies are in agreement with the calculated (B3LYP) scaled values. The phenyl and pyrone ring modes are identified and assigned. The predicted infrared intensities and Raman activities are reported.

The FT-IR and FT-Raman spectra of 5-chloro-2-(3-chlorophenylcarbamoyl)phenylacetate were studied. The vibrational wave numbers and corresponding vibrational assignments were examined theoretically using the Gaussian 03 set of quantum chemistry codes and the normal modes are assigned by Potential Energy Distribution calculations. The synthesis, elemental analysis and NMR values are presented. The red shift of the NH stretching wave number in the infrared spectrum from the computed wave number indicates the weakening of the NH bond resulting in proton transfer to the neighboring oxygen atom. The first hyperpolarizability, infrared intensities and Raman activities are reported. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive object for future studies of nonlinear optics. The geometrical parameters of the title compound are in agreement with that of similar reported derivatives. (C) 2011 Elsevier B.V. All rights reserved.

The Fourier transform infrared and Fourier transform Raman spectra of (E)-4-(benzylideneamino)-N-carbamimidoyl benzenesulfonamide were recorded and analyzed. Geometry and harmonic vibrational wavenumbers were calculated theoretically using Gaussian 03 set of quantum chemistry codes. Calculations were performed at the Hartree-Fock (HF) and density functional theory (DFT; B3PW91, B3LYP) levels of theory. The calculated wavenumbers (B3LYP) agree well with the observed wavenumbers. Potential energy distribution is done using GAR2PED program. The red shift of the N-H stretching band in the infrared spectrum from the computed wavenumber indicates the weakening of the N-H bond. The geometrical parameters of the title compound are in agreement with that of reported similar derivatives. The calculated first hyperpolarizability is comparable with the reported value of similar derivative and may be an attractive object for further studies of nonlinear optics. Potential energy surface scan studies have been carried out to understand the stability of planar and nonplanar structures of the molecule.

FT-IR and FT-Raman spectra of (E)-N-carbamimidoyl-4-((3,4-dimethoxybenzylidene) amino) benzenesulfonamide were recorded and analyzed. The vibrational wavenumbers were computed using HF/6-31G*, B3PW91/6-31G* and B3LYP/6-31G* basis. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands obtained experimentally. The results indicate that the B3LYP method is able to provide satisfactory results for predicting vibrational frequencies and structural parameters. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive object for future studies of non-linear optics. The geometrical parameters of the title compound are in agreement with that of similar derivatives.

Infrared and Raman spectroscopic analyses were carried out on 1-(4-methoxyphenyl)-4-methylanthraquinone ( 1 ). The interpretation of the spectra was aided by DFT calculations of the molecule. The vibrational wavenumbers were examined theoretically using the Gaussian 03 set of quantum chemistry codes, and the normal modes were assigned by potential energy distribution (PED) calculations. A computation of the first hyperpolarizability of the compound indicates that this class of substituted anthraquinones may be a good candidate as a NLO material. Optimized geometrical parameters of the compound are in agreement with similar reported structures.

The infrared and Raman spectra of (E)-4-((anthracen-9-ylmethylene)amino)-N-carbamimidoylbenzene sulfonamide have been recorded and analysed. Geometry and harmonic vibrational wavenumbers were calculated theoretically using Gaussian03 set of quantum chemistry codes. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands found in infrared and Raman spectra of the studied molecule. The red-shift of the NH stretching band in the infrared spectrum from the computed wavenumber indicates the weakening of the NH bond. The NH stretching band has split into a doublet in the IR spectrum owing to the Davydov coupling between neighbouring units. The geometrical parameters of the title compound are in agreement with the reported similar derivatives. The calculated first hyperpolarizability is comparable with the reported value of similar structures and may be an attractive object for further studies on non-linear optics. The important thermodynamical parameters are also reported.

The infrared and Raman spectra of N-carbamimidoyl-4-((2-hydroxybenzylidene) amino) benzenesulfonamide have been recorded and analyzed. Geometry and harmonic vibrational wavenumbers were calculated theoretically using Gaussian 03 set of quantum chemistry codes. Calculations were performed at the DFT (B3LYP) and MP2(SDD) levels of theory. The calculated wavenumbers (MP2) agree well with the observed wavenumbers. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands found in infrared and Raman spectra of the studied molecule. The red-shift of the N-H stretching band in the infrared spectrum from the computed wavenumber indicates the weakening of the N-H bond. The N-H stretching bands has split into a doublet, 3453, 3427 and 3355, 3225 cm(-1) in the IR spectrum owing to the Davydov coupling between neighboring units. The geometrical parameters of the title compound are in agreement with the reported similar derivatives.

The Fourier transform infrared (FT-IR) and FT-Raman spectra of sulfur trioxide-pyridine complex were recorded and analyzed. The potential-dependent surface-enhanced Raman scattering (SERS) was recorded from an electrochemically roughened silver electrode. The vibrational wave numbers of the compound were computed using the Hartree – Fock/6-31G ∗ basis and compared with the experimental values. The presence of strong pyridine ring vibrations in the SERS spectrum reveals the interaction between the pyridine ring and the silver surface. The molecule is adsorbed on the silver surface with the pyridine ring in a tilted orientation. The direction of charge-transfer contribution to the SERS is discussed from the frontier orbital theory. The value of the calculated first hyperpolarizability is comparable to those reported for similar structures, which makes this molecule an attractive object for future studies of nonlinear optics. The optimized geometrical parameters of the title compound are in agreement with similar reported structures. Copyright c � 2011 John Wiley & Sons, Ltd.

FT-Raman and FT-IR spectra of ASnFe(PO4)3 [A = Na2, Ca, Cd] were recorded and analyzed. The bands were assigned in terms of the vibrational group frequencies of SnO6 octahedral and PO4 tetrahedral. The spectral analysis shows that the symmetry of corner shared octahedral (SnO6) and the tetrahedral (PO4) are lowered from their free ion symmetry state. The presence of Fe3+ ions disrupts the S–N–O–S–N chain in the structure. This causes distortion of SnO6 and PO4 in the structure of all the compounds. Also it is seen that there are two distinct PO4 tetrahedra of different P–O bond lengths. One of these tetrahedra is linearly distorted in all the title compounds. The PO4 frequencies and bond lengths are calculated theoretically and are in agreement with the experimental values. The presence of PO4 polyanion in the structure can reduce the redox energy and hence reduce the metal oxygen covalency strength in the structure.

FT-IR and FT-Raman spectra of ethyl methyl ketone semicarbazone were recorded and analyzed. The vibrational wavenumbers were computed using HF/6-31G*, B3PW91/6-31G* and B3LYP/6-31G* basis and compared with experimental data. The first hyperpolarizability, infrared intensities and Raman activities are reported. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive object for future studies of non-linear optics. The extended π-electron delocalization over the carbazone moiety is responsible for the nonlinearity of the molecule. The geometrical parameters of the title compound are in agreement with that of similar derivatives. The red shift of the NH stretching wavenumber in the infrared spectrum from the computed wavenumber indicates the weakening of the NH bond resulting in proton transfer to the neighboring oxygen atom.

FT-IR and FT-Raman spectra of 1H-2,2-dimethyl-3H-phenothiazin-4[10H]-one were recorded and analyzed. The vibrational wavenumbers were computed using HF/6-31G(d) and B3LYP/6-31G(d) basis. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands obtained in infrared and Raman spectroscopies of the studied molecule. The first hyperpolarizability, infrared intensities and Raman activities are reported. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive object for future studies of non-linear optics. The geometrical parameters of the title compound are in agreement with XRD crystal structure data. The red shift of the N H stretching wavenumber in the infrared spectrum from the computed wavenumber indicates the weakening of the N H bond.

Di-2-pyridyl ketone nicotinoylhydrazone was prepared by condensation between appropriate aldehyde/ketone with the respective acid hydrazide. The FT-IR spectrum is recorded and analysed. The vibrational frequencies were computed using the HF/6-31G(d) and B3LYP/6-31G(d) basis and compared with experimental data. The infrared intensities and first hyperpolarizability are reported. The calculated data suggest an extended π-electron delocalization over the pyridyl and nicotinoyl hydrazone moieties which are responsible for the nonlinearity of the molecule. Optimized geometrical parameters (DFT) of the title compound are in agreement with similar reported structures.

FT-IR spectrum of quinoline-2-carbaldehyde benzoyl hydrazone (HQbH2O) was recorded and analyzed. The synthesis and crystal structure data are also described. The vibrational wavenumbers were examined theoretically using the Gaussian03 package of programs using HF/6-31G(d) and B3LYP/6-31G(d) levels of theory. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands obtained in infrared spectroscopy of the studied molecule. The first hyperpolarizability, infrared intensi- ties and Raman activities are reported. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive object for future studies of non-linear optics. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated values. The changes in the CAN bond lengths suggest an extended p-electron delocaliza- tion over quinoline and hydrazone moieties which is responsible for the non-linearity of the molecule.

FT-IR and FT-Raman spectra of ethyl methyl ketone thiosemicarbazone were recorded and analyzed. The crystal structure is also described. The vibrational wavenumbers were computed using HF/6–31G(d) and B3LYP/6–31G(d) basis sets and are assigned with the aid of MOLEKEL program. The first hyperpolarizability, infrared intensities and Raman activities are also reported. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive molecule for future applications in non-linear optics. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated values. The red shift of the NH stretching wavenumber in the infrared spectrum compared to the computed wavenumber indicates the weakening of the N–H bond resulting in proton transfer to the neighbouring sulfur atom.

The infrared and Raman spectra of 3‐{[(4‐methoxyphenyl)methylene]amino}‐2‐ phenylquinazolin‐4(3H)‐one have been recorded and analysed. Geo metry and harmonic vibrational wavenumbers were calculated theoretically using Gaussian 03 set of quantum chemistry codes. Calculations were performed at the Hartree‐Fock and DFT (B3LYP) levels of theory using the standard 6‐31G* basis. The calculated wavenumbers (B3LYP) agree well with the observed wavenumbers. The proposed assignments of normal modes are based on potential energy distribution (PED) analysis. Calculated infrar ed intensities and first hyperpolarizability are reported. The prepared compound was identified by NMR and mass spectra. The phenyl C‐C stretching modes are equally active as strong bands in both IR and Raman spectra, which are responsible for hyperpolarizability enhancement leading to nonlinear optical activity. The calculated first hyperpolarizability is comparable with the

The Fourier-transform infrared and Fourier-tranform Raman spectra of phenyl phosphate disodium salt were recorded and analyzed. The surface-enhanced Raman scattering (SERS) spectrum was recorded in a silver colloid. The vibrational wavenumbers of the compound were computed using the Hartree–Fock/6-31G* basis and compared with the experimental values. The molecule is adsorbed on the silver surface with the benzene ring in a tilted orientation. The presence of the phenyl ring and the phosphate group vibrations in the SERS spectrum reveal the interactions between the phenyl ring and the phosphate group with the silver surface. The first hyperpolarizability is calculated, and the calculated molecular geometry is compared with those of similar reported structures. Copyright © 2009 John Wiley & Sons, Ltd.

FT-Raman and FT-IR spectra of 3-amino-2-phenyl quinazolin-4(3H)-one were recorded and analyzed. The vibrational wavenumbers of the title compound have been computed using the HartreeFock/6-31G* and B3LYP/6-31G* basis sets and compared with the experimental data. The prepared compound was identified by NMR and mass spectra. The red shift of the NH stretching wavenumber indicates the weakening of the NH bond. The simultaneous IR and Raman activation of the Cdouble bond; length as m-dashO stretching mode gives the charge transfer interaction through a π-conjugated path. The first hyperpolarizability, Infrared intensities and Raman activities are reported. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive object for future studies of non-linear optics. The assignments of the normal modes are done by potential energy distribution (PED) calculations. Optimized geometrical parameters of the title compound are in agreement with reported similar structures.

IR, Raman and surface-enhanced Raman scattering (SERS) spectra of sulfanilic acid sodium salt (SANA) were recorded and analysed. The vibrational wavenumbers were computed by the density functional theory method using the B3LYP/6–31G* basis and found to be in good agreement with the experimental values. The effect of concentration and pH dependence on the SERS intensity of the molecule was also studied. The molecular plane assumes a tilted orientation with respect to the silver surface. The observed changes of the relative intensities of some enhanced bands and the presence of in-plane and out-of-plane modes of the phenyl ring suggest that the molecule assumes a more tilted orientation upon lowering the concentration of the adsorbate. Copyright © 2009 John Wiley & Sons, Ltd.

The Fourier transform Raman (FT-Raman) and Fourier transform infrared (FT-IR) spectra of 2-[acetyl(4-bromophenyl)carbamoyl]-4-chlorophenyl acetate were studied. The vibrational wavenumbers were examined theoretically using the Gaussian03 set of quantum chemistry codes, and the normal modes were assigned by potential energy distribution (PED) calculations. The simultaneous Raman and infrared (IR) activations of the CO stretching mode in the carbamoyl moiety show a charge transfer interaction through a π-conjugated path. From the optimized structure, it is clear that the hydrogen bonding decreases the double bond character of the CO bond and increases the double bond character of the CN bonds. The first hyperpolarizability and predicted IR intensities are reported. The calculated first hyperpolarizability is comparable with the reported values of similar structures, which makes this compound an attractive object for future studies of nonlinear optics. Optimized geometrical parameters of the compound are in agreement with similar reported structures. Copyright © 2009 John Wiley & Sons, Ltd.

Raman and FTIR spectra of guanidinium zinc sulphate [C(NH 2 ) 3 ] 2 Zn(SO 4 ) 2 are recorded and the spectral bands assignment is carried out in terms of the fundamental modes of vibration of the guanidinium cations and sulphate anions. The analysis of the spectrum reveals distorted SO 4 2− tetrahedra with distinct S–O bonds. The distortion of the sulphate tetrahedra is attributed to Zn–O–S–O–Zn bridging in the structure as well as hydrogen bonding. The CN 3 group is planar which is expressed in the twofold symmetry along the C–N (1) vector. Spectral studies also reveal the presence of hydrogen bonds in the sample. The vibrational frequencies of [C(NH 2 ) 3 ] 2 and HC(NH 2 ) 3 are computed using Gaussian 03 with HF/6-31G* as basis set.

The IR and Raman spectra of ethyl salicylate were recorded and analyzed. The surface enhanced Raman scattering (SERS) spectrum was recorded in a silver colloid. The vibrational wavenumbers of the compound have been computed using the Hartree-Fock/6-31G* basis. The direction of charge transfer contribution to SERS has been discussed from the frontier orbital theory. The presence of methyl modes in the SERS spectrum indicates the nearness of the methyl group to the metal surface and the presence of ring vibrations and out-of-plane ring modes in the SERS spectrum suggests a flat orientation of the molecule on the silver surface. The first hyperpolarizability is calculated and the calculated molecular geometry has been compared with the reported similar structures. Copyright © 2009 John Wiley & Sons, Ltd.

The FT-IR and FT-Raman spectra of anilinium sulfate were recorded and analyzed. The surface-enhanced Raman scattering (SERS) was recorded from a silver electrode. The vibrational wavenumbers of the compound have been computed using the Hartree-Fock/6-31G ∗ basis and compared with the experimental values. The molecule is adsorbed on the silver surface with the benzene ring in a tilted orientation. The presence of amino and sulfate group vibrations in the SERS spectrum reveal the interactionbetween aminoand sulfate groups with thesilver surface. The direction of thecharge transfercontribution to SERS has been discussed from the frontier orbital theory. Copyright c � 2009 John Wiley & Sons, Ltd. Supportinginformationmaybefoundintheonlineversionofthisarticle.

Fourier transform infrared (FT-IR) and Fourier transform (FT) Raman spectra of 3-{[(2-hydroxyphenyl)methylene]amino}-2phenylquinazolin-4(3H)-onewererecordedandanalyzed.Thevibrationalwavenumbersof thetitlecompound werecomputed usingHF/6-31G ∗ and6-311G ∗ basissetsandcomparedwithexperimentaldata.Theassignmentsofthenormalmodesaredone by potential energy distribution (PED)calculations. The prepared compound was identified by nuclear magnetic resonance (NMR) and mass spectra. Optimized geometrical parameters of the title compound are in agreement with reported structures. ShorteningofCNbondlengthsrevealtheeffectofresonance.ThesimultaneousIRandRamanactivationsoftheC Ostretching mode shows a charge transfer interaction through a π-conjugated path. The first hyperpolarizability, infrared intensities and Raman activities are reported. The phenyl C‐C stretching modes are equally active as strong bands in both IR and Raman spectra, which are responsible for hyperpolarizability enhancement leading to nonlinear optical activity. Copyright c

Fourier transform (FT)-Raman and Fourier transform infrared (FT-IR) spectra of 3-{[(4-fluorophenyl)methylene]amino}-2-phenylquinazolin-4(3H)-one were recorded and analyzed. The vibrational wavenumbers of the title compound were computed using the B3LYP/6-31G* basis and compared with the experimental data. The prepared compound was identified by NMR and mass spectra. The simultaneous IR and Raman activation of the CO stretching mode shows a charge transfer interaction through a π-conjugated path. The first hyperpolarizability and infrared intensities are reported. The assignments of the normal modes are done by potential energy distribution (PED) calculations. Copyright © 2008 John Wiley & Sons, Ltd.

Fourier transform infrared (FT-IR) and FT-Raman spectra of 4-fluoro-N-(2-hydroxy-4-nitrophenyl)benzamide were recorded and analyzed. The vibrational wavenumbers and corresponding vibrational assignments were examined theoretically using the Gaussian03 set of quantum chemistry codes. The red-shift of the NH-stretching wavenumber in the infrared (IR) spectrum from the computed wavenumber indicates the weakening of the NH bond resulting in proton transfer to the neighboring oxygen atom. The simultaneous IR and Raman activation of the CO-stretching mode gives the charge transfer interaction through a π-conjugated path. Copyright © 2008 John Wiley & Sons, Ltd.

5,6-Dihydro-6-styryl-2-pyrone (Goniothalamin), is isolated from the leaves of Goniothalamus wightii and identified by spectral analysis and X-ray diffraction studies. FT-IR spectroscopy has also been used to characterize the vibrational bands. The vibrational wavenumbers and corresponding vibrational assignments are examined theoretically using the Gaussian03 set of quantum chemistry codes. Predicted IR and Raman intensities are reported.

FT-IR spectra of 5-methyl-2-(p-methylaminophenyl)benzoxazole was recorded and analysed. The vibrational frequencies of the compound have been computed using the Hartree-Fock/6-31G* basis and compared with the experimental values.