Traditional vibrational assignment in terms of bond stretching, angle bending, and torsion is not possible in fullerenes due to the very large number of coupled internal coordinates. Large scale density functional calculations of the vibrational properties of C60 and C60 have been carried out with Becke3LYP and BeckeLYP exchange-correlation functionals in the pursuit of obtaining a reliable set...

A systematic vibrational spectroscopic assignment and analysis of pregabalin has been carried out by using FTIR, FT-Raman spectral data. The vibrational analysis were aided by electronic structure calculations-hybrid density functional methods (B3LYP) performed with 631G(d,p) basis set. Molecular equilibrium geometries, electronic energies, natural bond order analysis, IR intensities, and harmo...

The structure of beryllium acetylacetonate, Be(acac)(2), was fully optimized at the B3LYP (using the 6-31G*, 6-311G*, and 6-311++G(3df,2p) basis sets), Hartree-Fock, and the Möller-Plesset (using the 6-31G* basis set) levels. The frequency and intensity of the vibrational bands of Be(acac)(2) and its 1,3,5-(13)C; 2,4-(13)C; 3-(2)H; 3-(2)H-2,4-(18)O derivatives were obtained at the B3LYP level u...

The vibrational modes of three solid AlF3 phases (alpha, beta, and amorphous high surface area AlF3) are investigated. Calculations have been performed using hybrid exchange correlation functionals to determine the equilibrium geometries and Gamma-point phonon frequencies for the alpha-AlF3 and beta-AlF3 phases. The calculated optical modes are in excellent agreement with experiment. The IR abs...

Over the last few decades, infrared (IR) spectroscopy has been recognized as a useful tool to obtain quantitative and qualitative information on IR active materials and bio-materials, with particular emphasis to polymer chemistry and organic chemistry. Nowadays, thanks to technological evolution, the possibilities offered by vibrational spectroscopy (e.g. IR and Raman spectroscopy) are much bro...

The L-alanine family crystals such as pure L-Alanine, hydrochloride (HCl) mixed Lalanine, potassiumchloride (kcl) mixed l-alanine and potassium dihydrogen phosphate (kdp) mixed l-alanine have been successfully grown from the aqueous solution by slow evaporation method at room temperature. The grown crystals FT-IR spectral studies were recorded for each sample and the molecular vibrational frequ...

Octafluorocyclobutane, c-C4F8, and its derivatives are regarded as promising replacements of insulation gaseous SF6, which are currently widely used in electric equipment but suffer greatly from its greenhouse effect. Based on the recent finding that the dielectric and thermodynamics properties of insulating gases are greatly dependent on the molecule's microscopic electronic and vibrational pa...

The numerical-analytic implementation of the operator version of the canonical Van Vleck second-order vibrational perturbation theory (CVPT2) is employed for a purely ab initio prediction and interpretation of the infrared (IR) and Raman anharmonic spectra of a medium-size molecule of the diketo tautomer of uracil (2,4(1H,3H)-pyrimidinedione), which has high biological importance as one of the ...

Ultrafast two-dimensional infrared (2D-IR) vibrational echo spectroscopy can probe the fast structural evolution of molecular systems under thermal equilibrium conditions. Structural dynamics are tracked by observing the time evolution of the 2D-IR spectrum, which is caused by frequency fluctuations of vibrational mode(s) excited during the experiment. However, there are a variety of effects th...

Self-association of alcohols; including ethanol, methanol, cyclopentanol and octanol in separate mixtures with inert solvents have been studied using FT-IR spectroscopy. Except for the band at 3640 cm–1 in the IR spectrum of the alcohols which is due to the monomer species, the presence of other bands in the region of stretching vibrational frequencies of OH (3100-3700 cm–1) are attributed to t...