NIR‐FT Raman and FT‐IR spectral investigations of the nonlinear optical chromophore p ‐bromoacetanilide

Panicker²,

Madhavan³

et al. 2009

FT-IR and FT-Raman spectra of 4-chloro-2-(4-bromophenylcarbamoyl)phenyl acetate 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 neighbouring oxygen atom. The simultaneous IR and Raman activations of the C O stretching mode give the charge transfer interaction through a π -conjugated path. Optimized geometrical parameters of the title compound are in agreement with similar reported structures. From the optimized structure, it is clear that the hydrogen bonding decreases the double bond character of C O bond and increases the double bond character of the C-N bonds. The first hyperpolarizability, predicted infrared intensities and Raman activities are reported. The calculated first hyperpolarizability is comparable with the reported values of similar derivativesand 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.

Section: Geometrical Parameters and First Hyperpolarizabilitysupporting

confidence: 74%

FT‐IR, FT‐Raman and DFT calculations of the salicylanilide derivate 4‐chloro‐2‐(4‐bromophenylcarbamoyl)phenyl acetate

Panicker²,

Madhavan³

et al. 2009

“…The calculated first hyperpolarizability of the title compound is 80.04 × 10 −30 esu, which is comparable to the reported values of similar derivatives, [82] but experimental evaluation of this data is not readily available. We conclude that the title compound is an attractive object for future studies of nonlinear optical properties.…”

Section: First Hyperpolarzability and Geometrical Parameterssupporting

confidence: 72%

Spectroscopic investigations and computational study of sulfur trioxide–pyridine complex

Anto

et al. 2011

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.

“…The calculated first hyperpolarizability of the title compound is 1.875 × 10 −30 esu, which is comparable with the reported values [66] and experimental evaluation of this data is not readily available. We conclude that the title compound is an attractive object for future studies of non-linear optical properties.…”

Section: Geometrical Parameters and Hyperpolarizabilitysupporting

confidence: 78%

IR, Raman and SERS spectra of ethyl salicylate

Panicker¹,

Ushakumary³

2009

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.