Nonadiabatic wavefunctions as linear expansions of correlated exponentials. A quantum Monte Carlo application to H 2+ and Ps 2
Abstract
We propose to expand the nonadiabatic solution of the Schrödinger equation as a linear combination of explicity correlated exponentials. A series of trial wavefunctions has been optimized minimizing the variance of the local energy for the H 2+ and dipositronium (Ps 2) molecules in their ground state, without resorting to the Born-Oppenheimer approximation: the calculations have been performed using the variational Monte Carlo method. In a diffusion Monte Carlo simulation a 6-term wavefunction allowed us to compute the exact energy of the Ps 2 system -0.51601 hartree with a variance of 0.00001 hartree.
- Publication:
-
Chemical Physics Letters
- Pub Date:
- July 1997
- DOI:
- 10.1016/S0009-2614(97)00571-X
- Bibcode:
- 1997CPL...272..370B