Calculating molecular vibrational spectra beyond the harmonic approximation |
| |
Authors: | Ching Yeh Lin Andrew T B Gilbert Peter M W Gill |
| |
Institution: | (1) Research School of Chemistry, Australian National University, Canberra, ACT, 0200, Australia |
| |
Abstract: | We present a new approach for calculating anharmonic corrections to vibrational frequency calculations. The vibrational wavefunction
is modelled using translated Hermite functions thus allowing anharmonic effects to be incorporated directly into the wavefunction
whilst still retaining the simplicity of the Hermite basis. We combine this new method with an optimised finite-difference
grid for computing the necessary third and fourth nuclear derivatives of the energy. We compare our combined approach to existing
anharmonic models—vibrational self-consistent field theory (VSCF), vibrational perturbation theory (VPT), and vibrational
configuration interaction theory (VCI)—and find that it is more cost effective than these alternatives. This makes our method
well-suited to computing anharmonic corrections for frequencies in medium-sized molecules.
Contribution of the Mark S. Gordon 65th Birthday Festschrift Issue. |
| |
Keywords: | PES VPT TOSH Anharmonic Vibrational frequencies Potential energy surface Perturbation Nuclear vibration theory Quartic force field |
本文献已被 SpringerLink 等数据库收录! |