Papers by Jaccob Madhavan
… Acta Part A: Molecular …, Jan 1, 2008
The FTIR and FT-Raman spectra of morpholine-4-ylmethylthiourea (MMTU) were recorded in the region... more The FTIR and FT-Raman spectra of morpholine-4-ylmethylthiourea (MMTU) were recorded in the region of mid-IR (400-4,000 cm(-1)). Initial geometry generated from the standard geometrical parameters was relaxed without any constraint on the potential energy surface at MP2 and DFT levels adopting the standard 6-31++G and 6-311+G basis set. With the help of two specific scaling procedures the computed harmonic frequencies have been compared with the observed vibrational wave numbers of FTIR and FT-Raman spectra and assigned to different normal modes of the molecule. Most of the vibrational modes have wave numbers in the expected range. The appropriate theoretical spectrograms of the IR spectra of MMTU have been also constructed.
… of Photochemistry and …, Jan 1, 2008
… Journal of Quantum …, Jan 1, 2010
Abstract Correlated ab initio molecular orbital, DFT, QCISD, G3MP2, and QCISD (T) calculations ha... more Abstract Correlated ab initio molecular orbital, DFT, QCISD, G3MP2, and QCISD (T) calculations have been used to investigate the geometries, energetics, and mechanisms governing the insertion reactions of 1 CH 2 into O [BOND] H and N [BOND] H bonds of water and ammonia, respectively, in gas phase adopting 6-311++ g (d, p) basis set. It is found that 1 CH 2 reacts with water and ammonia to produce the ylide-like intermediates H 2 C [BOND] OH 2 and H 2 C [BOND] NH 3, which in turn undergo 1, 2-hydrogen shift to produce ...
Journal of Chemical …, Jan 1, 2009
Journal of Physical …
Abstract Cyclobutene undergoes electrocyclic ring opening through conrotatory mode to give 1, 3-b... more Abstract Cyclobutene undergoes electrocyclic ring opening through conrotatory mode to give 1, 3-butadiene and similarly its skeletally substituted analogues viz. phosphetene, thietene, oxetene and azetene isomerize to give their respective heterodienes. Quantum mechanical investigations on these perturbed pericyclic isomerizations at B3LYP level with 6-31G (d) and 6-311+ G (d, p) basis sets reveal that hetero-atoms significantly lower the barrier and alter the reaction free energies. Interestingly frontier orbital correlation diagram ...
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Papers by Jaccob Madhavan