1. Quantum and classical vibrational relaxation dynamics ofN-methylacetamide on ab initio potential energy surfaces
- Author
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Fujisaki, Hiroshi, Yagi, Kiyoshi, Hirao, Kimihiko, Straub, John E., and Stock, Gerhard
- Subjects
Chemical Physics (physics.chem-ph) ,Physics ,Quantum dynamics ,Ab initio ,Degrees of freedom (physics and chemistry) ,FOS: Physical sciences ,Configuration interaction ,Condensed Matter Physics ,Potential energy ,Molecular physics ,Atomic and Molecular Physics, and Optics ,Biological Physics (physics.bio-ph) ,Physics - Chemical Physics ,Physics::Atomic and Molecular Clusters ,Vibrational energy relaxation ,Relaxation (physics) ,Physics - Biological Physics ,Physics::Chemical Physics ,Physical and Theoretical Chemistry ,Perturbation theory - Abstract
Employing extensive quantum-chemical calculations at the DFT/B3LYP and MP2 level, a quartic force field of isolated N-methylacetamide is constructed. Taking into account 24 vibrational degrees of freedom, the model is employed to perform numerically exact vibrational configuration interaction calculations of the vibrational energy relaxation of the amide I mode. It is found that the energy transfer pathways may sensitively depend on details of the theoretical description. Moreover, the exact reference calculations were used to study the applicability and accuracy of (i) the quasiclassical trajectory method, (ii) time-dependent second-order perturbation theory, and (iii) the instantaneous normal mode description of frequency fluctuations. Based on the results, several strategies to describe vibrational energy relaxation in biomolecular systems are discussed., Comment: 18 pages, 6 figures, submitted to J. Phys. Chem. A
- Published
- 2009