First principles semiclassical calculations of vibrational eigenfunctions

Abstract

Vibrational eigenfunctions are calculated on-the-fly using semiclassical methods in conjunction with ab initio density functional theory classical trajectories. Various semiclassical approximations based on the time-dependent representation of the eigenfunctions are tested on an analytical potential describing the chemisorption of CO on Cu(100). Then, first principles semiclassical vibrational eigenfunctions are calculated for the CO 2 molecule and its accuracy evaluated. The multiple coherent states initial value representations semiclassical method recently developed by us has shown with only six ab initio trajectories to evaluate eigenvalues and eigenfunctions at the accuracy level of thousands trajectory semiclassical initial value representation simulations.

Accelerated direct semiclassical molecular dynamics using a compact finite difference Hessian scheme

“…(8) and (9). For these reasons, recently the MC-SC-IVR method was developed by Ceotto et al [55][56][57] This SC-IVR implementation enhances as much as possible the overlap between the reference state |χ and the exact quantum eigenfunctions. As a result, representation of spectral peaks for excited vibrational states are less noisy, more intense and accurate.…”

Fighting the curse of dimensionality in first-principles semiclassical calculations: Non-local reference states for large number of dimensions

“…50 Finally, accurate vibrational eigenfunctions for the CO 2 molecule were reproduced still on-the-fly. 51 As mentioned in the introduction, in this manuscript, we strive to extend the MC-SC-IVR approach to deal with system with several degrees of freedom. As stressed in the introduction, useful simulations would be those where the recurrence overlap occurs on all dimensions simultaneously.…”

A correlated-polaron electronic propagator: Open electronic dynamics beyond the Born-Oppenheimer approximation

“…[24][25][26][27][28][29][30] In the latter approach, the electronic degrees of freedom are described as a superposition of a few adiabatic surfaces, and nuclear wave-packets are studied in the dynamics. In our approach, the electronic degrees of freedom are described in all-electron detail, but the dynamics of the nuclei are approximated by the choice of the Holstein Hamiltonian.…”