V P Gupta
Articles written in Pramana – Journal of Physics
Volume 16 Issue 5 May 1981 pp 369-373 Molecular Physics
Atom-dipole interaction model has been used to calculate the molecular polarizabilities, refractive indices along the direction of principal polarizabilities of glycine and L-alanine and the molar optical rotation of L-alanine. The results of the calculation have been compared with experimentally observed data from Kerr effect and polarimetric measurements.
Volume 67 Issue 3 September 2006 pp 487-501 Research Articles
A theoretical study of the mechanism of photodecomposition in carbonyl cyanide, diethynyl ketone, acetyl cyanide and formyl cyanide has been conducted using density functional and MP2 theories. A complete analysis of the electronic spectra of these molecules in terms of nature, energy and intensity of electronic transitions has been provided by time-dependent density functional theory. Mixing coefficients and main configurations of the electronic states have been used to identify the states leading to the photodecomposition process. While the Rydberg state 1(n,3s) is involved in the dissociation of formyl cyanide and acetyl cyanide, the π*CC/π*CN states are involved in the case of carbonyl cyanide and diethynyl ketone. In all cases, however, stepwise decomposition process is preferred over the concerted reaction process. Based on potential energy curves for bond dissociation and the transition state and IRC studies, it is found that besides the direct dissociation of carbonyl cyanide, a photoisomerization process through a non-planar transition state may also occur resulting in the formation of a stable and planar isomer CNC(O)CN. A complete vibrational analysis of the higher energy isomer has been conducted and several new fundamental bands are predicted. Some of the earlier experimental results on the photodecomposition mechanism and energies of photofragments in carbonyl cyanide and acetyl cyanide have been rationalized.
Volume 93 | Issue 5
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