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FT-Raman Spectra (ft-raman + spectrum)
Selected AbstractsA Computational and Experimental Study of the Structure and Raman and 77Se NMR Spectra of SeX3+ and SeX2 (X: Cl, Br, I): FT-Raman Spectrum of (SeI3)[AsF6].CHEMINFORM, Issue 23 2005J. Mikko Rautiainen Abstract For Abstract see ChemInform Abstract in Full Text. [source] FT-Raman, FT-IR spectral and DFT studies on 6, 8-dichloroflavone and 6, 8-dibromoflavoneJOURNAL OF RAMAN SPECTROSCOPY, Issue 7 2010Yusuf Erdogdu Abstract In this study, experimental and theoretical vibrational spectral results of the molecular structures of 6,8-dichloroflavone (6,8-dcf) and 6,8-dibromoflavone (6,8-dbf) are presented. The FT-IR and FT-Raman spectra of the compounds have been recorded together between 4000 and 400 cm,1 and 3500,5 cm,1 regions, respectively. The molecular geometry and vibrational wavenumbers of 6,8-dcf and 6,8-dbf in their ground state have been calculated by using DFT/B3LYP functional, with 6-31 + + G(d,p) basis set used in calculations. All calculations were performed with Gaussian03 software. The obtained vibrational wavenumbers and optimized geometric parameters were seen to be in good agreement with the experimental data. Scale factors have been used in order to compare how the calculated and experimental data are in agreement. Theoretical infrared intensities are also reported. Copyright © 2009 John Wiley & Sons, Ltd. [source] Density functional theory calculations and vibrational spectra of p -bromonitrobenzeneJOURNAL OF RAMAN SPECTROSCOPY, Issue 8 2009V. Krishnakumar Abstract FT-IR and FT-Raman spectra of p -bromonitrobenzene (p-BNB) have been recorded in the region 4000,400 cm,1 and 4000,50 cm,1, respectively. The molecular structure, geometry optimization, vibrational wavenumbers have been investigated. The spectra were interpreted with the aid of normal coordinate analysis based on the density functional theory (DFT) using the standard B3LYP/6-31G method and basis set combination and was scaled using multiple scale factors yielding good agreement between observed and calculated wavenumbers. The results of the calculations are applied to simulate infrared and Raman spectra of the title compound which showed reasonable agreement with the observed spectra. Copyright © 2009 John Wiley & Sons, Ltd. [source] Theoretical and vibrational spectral investigation of sodium salt of acenocoumarolJOURNAL OF RAMAN SPECTROSCOPY, Issue 8 2009I. Hubert Joe Abstract The FT-IR and FT-Raman spectra of sodium salt of 4-hydroxy-3[1-(4-nitrophenyl)-3-oxobutyl]-2H -1-benzopyran-2-one (acenocoumarol sodium salt) in solid phase have been recorded and analyzed. The optimization geometry, intramolecular hydrogen bonding, and harmonic vibrational wavenumbers of acenocoumarol sodium salt have been investigated with the help of B3LYP density functional theory (DFT) methods. The infrared and Raman spectra were predicted theoretically from the calculated intensities. Natural bond orbital (NBO) analysis indicates the presence of CH···O hydrogen bonding in the molecule. The first static hyperpolarizability of the molecule has been computed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Vibrational spectroscopic studies and DFT calculations of 4-fluoro- N -(2-hydroxy-4-nitrophenyl)benzamideJOURNAL OF RAMAN SPECTROSCOPY, Issue 12 2008L. Ushakumari Abstract 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 ,-conjugated path. Copyright © 2008 John Wiley & Sons, Ltd. [source] Vibrational spectra and quantum chemical calculations of uracilyl,pyridinium mesomeric betaineJOURNAL OF RAMAN SPECTROSCOPY, Issue 11 2007A. Schmidt Abstract Modified nucleobases (MNs) are promising molecules with potential application in non-linear optic (NLO) and drug design against a wide number of diseases. In the present paper we report studies on a cross-conjugated mesomeric betaine, which can act as a MN, formed by the covalent union of a 4-dimethylamino pyridinium and a uracilyl groups. The molecule thus formed must be presented by a dipolar canonical formulae in which positive and negative charges are delocalized within separated moieties. Quantum chemistry density functional theory (DFT) calculations, at the B3PW91/6-31G** level, and Fourier transform (FT) infrared and Raman spectra of this molecule and its N -deuterated derivative were performed. The calculated structural properties over the ground state optimized structure evidenced a strong separation between the two conjugated systems. Comparison with previous results obtained for the cationic species indicated that N -protonation clearly affects the degree of conjugation. Assignments of the FT-IR and FT-Raman spectra were supported by the DFT wavenumbers, intensities and normal modes, which also evidenced the separation of the two conjugated systems. Significant deviations were found for the stretching force constants of the inter-ring and the uracilyl skeletal bonds when comparing this molecule with its N -protonated species. Copyright © 2007 John Wiley & Sons, Ltd. [source] Ab initio vibrational calculations on ara-T molecule: Application to analysis of IR and Raman spectraBIOPOLYMERS, Issue 4 2001Belén Hernández Abstract The FTIR and FT-Raman spectra are reported for the arabinonucleoside ara-T (1-,- D -arabinofuranosylthymine), which shows antiviral activity. The accurate knowledge of the vibrational modes is a prerequisite for the elucidation of drug,nucleotide and drug,enzyme interactions. The FTIR and FT-Raman spectra of ara-T were recorded from 4000 to 30 cm,1. A tetradeuterated derivative (deuteration at N3, and hydroxyl groups O,2, O,3, and O,5) was synthesized and the observed isotopic shifts in its spectra were used for the vibrational analysis of ara-T. The theoretical frequencies and the potential energy distribution (PED) of the vibrational modes of ara-T were calculated using the ab initio Hartree,Fock/3-21G method. An assignment of the vibrational spectra of ara-T is proposed considering the scaled PED and the observed band shifts under deuteration. The scaled ab initio frequencies were in reasonable agreement with the experimental data. © 2001 John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 62: 193,207, 2001 [source] | ||||||||||