: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Guidelines for the use and interpretation of adsorption isotherm models: A review.

We report an improved synthesis of colloidal gold nanorods (NRs) by using aromatic additives that reduce the concentration of hexadecyltrimethylammonium bromide surfactant to ∼0.05 M as opposed to 0.1 M in well-established protocols. The method optimizes the synthesis for each of the 11 additives studied, allowing a rich array of monodisperse gold NRs with longitudinal surface plasmon resonance tunable from 627 to 1246 nm to be generated. The gold NRs form large-area ordered assemblies upon slow evaporation of NR solution, exhibiting liquid crystalline ordering and several distinct local packing motifs that are dependent upon the NR’s aspect ratio. Tailored synthesis of gold NRs with simultaneous improvements in monodispersity and dimensional tunability through rational introduction of additives will not only help to better understand the mechanism of seed-mediated growth of gold NRs but also advance the research on plasmonic metamaterials incorporating anisotropic metal nanostructures.

Improved Size-Tunable Synthesis of Monodisperse Gold Nanorods through the Use of Aromatic Additives

Spectrometric Identification of Organic Compounds

Studies on surface plasmon resonance and photoluminescence of silver nanoparticles

A complete vibrational spectrum analysis of 4-hydroxyacetanilide is performed. The wavenumbers are calculated on the basis of density functional theory using B3LYP/6-31G* basis set.Vibrational analysis indicates that the lowering of stretching wavenumbers of methyl group due to electronic effects simultaneously caused by inducation and hyperconjugation is due to the presence of the oxygen atom. Comparison of the observed fundamental vibrational wavenumbers of 4-hydroxyacetanilide with calculated results is found in agreement with the experimental data. The predicted infrared intensities and force constants are reported.

Vibrational Spectroscopic Studies and Dft Calculations of 4-Hydroxyacetanilide

A complete vibrational spectrum analysis of p-chlorobenzenesulfonic acid has been performed. The wavenumbers are calculated on the basis of ab initio theory using Hartree-Fock/6-31G* basis set. The predicted infrared intensities, Raman activities and force constnats 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 calculated geometrical parameters are also in agreement with reported values.

Vibrational Spectroscopic Studies and ab initio Calculations of p- Chlorobenzenesulfonic Acid

Natural Bond Orbital (NBO) Analysis of Certain Salicylanilide Derivatives

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.

http://www.orientjchem.org/pds/OJCV029I01P347-352.pdf

Vibrational Spectroscopic Studies of 4-chloro-3-methylphenol

FT-IR and FT-Raman spectra of 1,2-diphenyl-4-n-Butyl-3,5-pyrazolidinedione (Phenylbutazone) were recorded and analyzed. The vibrational wavenumbers were computed using HF/6-31G(d) and B3LYP/6-31G(d) basis sets and compared with experimental data. The first hyperpolarizability, infrared intensities and Raman activities are also reported. The geometrical parameters of the title compound obtained from theoretical calculations are in agreement with that of reported similar derivatives. The first hyperpolarizability is comparable with reported values of similar derivatives and is an attractive molecule for future applications in non-linear optics. The variation in C-N bond lengths suggests an extended πelectron delocalization over the pyrazolidinedione moiety which is responsible for the nonlinearity of the molecule.

Hema Tresa Varghese

Papers

Vibrational Spectroscopic Studies and Dft Calculations of 4-Hydroxyacetanilide

Vibrational Spectroscopic Studies and ab initio Calculations of p- Chlorobenzenesulfonic Acid

Natural Bond Orbital (NBO) Analysis of Certain Salicylanilide Derivatives

Vibrational Spectroscopic Studies of 4-chloro-3-methylphenol

Vibrational spectroscopic studies and computational study of 1,2-diphenyl-4-n-butyl-3,5-pyrazolidinedione