M Durga Prasad
Articles written in Journal of Chemical Sciences
Volume 99 Issue 1-2 August 1987 pp 61-65
The efficacy of using time-dependent generalizations of the closed shell coupled cluster method for intramolecular processes associated with non-degenerate vacuum in the context of molecular absorption spectra is examined. Since the separability requirements are built into such an ansatz for the time evolution operator, it is possible to develop approximations which can take into account any number of modes, with much less computational effort than in a calculation by basis set expansion.
Volume 129 Issue 7 July 2017 pp 953-961 REGULAR ARTICLE
Computed vibronic spectra of four molecules, tetracene, octatetraene, anthracene and pyrene are compared to the experimental spectra with a view to determine the functional that can give the best description. Using a statistical analysis, it is found that M06-2X is best suited for reproducing the 0-0 transition energy while PBE0 and M06 are the best suited functionals for predicting the vibrational frequencies. All the functionals perform equally well in predicting the intensities of vibronic transitions.
Volume 132 All articles Published: January 2020 Article ID 0014
A theory for calculating vibrational energy levels and infrared intensities is developed in the equation of motion framework at the random phase approximation level. The vibrational Hamiltonian is expanded in the harmonic oscillator ladder operators making a Hamiltonian a bosonic Hamiltonian. Theexcitation operator is expanded to include at most two creations and two annihilation operators making it equivalent to the random phase approximation. The method is applied for the calculation of vibrational spectral properties of two molecules. The results are found to be satisfactory, making this approach a viable option for large molecular systems.
Volume 134, 2022
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