Articles written in Journal of Chemical Sciences
Volume 87 Issue 10 October 1978 pp 337-346 Physical and Theoretical
Symmetry force field calculations have been performed for the planar vibrations of urea using CNDO/Force method. The CNDO/Force calculations predict well the signs and the magnitudes of bending and interaction force constants; the stretching force constants are found to be higher in magnitude. The bending and interaction constants obtained from these calculations and the stretching force constants obtained from the literature are considered for the initial force field. Using the observed frequencies for urea and its isotopic analogues, urea-D4, urea-15N2, urea-15N2D4 and urea-18O in the solid as well as in the solution phases, the force field is refined by carrying out iterations over the diagonal force constants. In the final stages of the refinement iterations are carried out over all the force constants keeping the signs of the interaction constants unchanged. It is found that the agreement between the calculated and the observed frequencies is excellent. The final force fields in terms of symmetry as well as redundancy free internal valence coordinates are reported. On the basis of the potential energy distribution the vibrational assignments are discussed.
Volume 93 Issue 6 August 1984 pp 917-926 Physical and Teoretical Chemistry
Various methods, employing molecular orbital calculations of varying approximations, for evaluation of force fields of polyatomic molecules have been reviewed. Applications of
Volume 95 Issue 5-6 December 1985 pp 499-508 Physical and Theoretical
Raman spectra of solutions of
Volume 96 Issue 3-4 February 1986 pp 285-290
The geometry optimization of monomeric acetonitrile and its dimers is carried out using CNDO/force method. The results are compared with the experimental and already reported theoretical parameters.
Volume 99 Issue 4 October 1987 pp 253-260 Physical and Theoretical
CNDO/force calculations on the complexes of nitromethane and acetonitrile with H+, Li+, F− and Cl− have been carried out to determine their geometrical parameters and stretching force constants. The results are discussed in terms of specific interactions between the ions and the molecules.
Volume 100 Issue 5 October 1988 pp 413-424 Physical and Theoretical
CNDO/force calculations have been employed to calculate the O-H stretching force constants for various structures of associated water species such as water-dimethylether, water-acetonitrile, water-lithium fluoride, linear and cyclic water polymers. The variation in the O-H stretching force constant in Am… O-H… Dn species where Am
Volume 105 Issue 1 February 1993 pp 71-78 Physical and Theoretical
Near infrared (NIR) spectra in the CH3 stretching first-overtone region for methyl iodide, acetonitrile, nitromethane and dimethyl sulphoxide are discussed in terms of normal mode and local mode descriptions. NIR spectra in this region for solutions of several alkali metal halides and tetraalkyl ammonium halides in these solvents are also reported. It is found that the relative intensity of the cooperative excitation band with respect to the pure overtone excitation band reduces considerably on increase in the concentration of the electrolytes in solution. The results are discussed in terms of the formation of anion-molecular complexes as well as intermode coupling due to kinetic energy and anharmonicity effects.
Volume 106 Issue 2 April 1994 pp 339-351
Volume 106 Issue 6 November 1994 pp 1315-1320
Volume 109 Issue 3 June 1997 pp 181-188 Physical And Theoretical
Using local mode description for methyl chloride, the infrared intensities for the first four CH3 stretching overtone bands are used to calculate the dipole function for the C-H bond. Detailed expressions for overtone transitions for diatomic molecules derived by Bouanich are employed for the calculation of dipole moment derivatives.
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