Physical Sciences and Mathematics Commons^™

Path integral Monte Carlo techniques are used to study Na3+ and Na3 at finite temperatures. In accord with previous classical trajectory calculations, we find that vibrational motion significantly distorts the clusters from the previously predicted zero temperature geometries, due to the flat Born-Oppenheimer potential energy surface. More importantly, these distorted clusters show significant localized electronic bonding, in contrast to the delocalized bonding found in previous studies of the zero temperature structures.

Path integral Monte Carlo and density functional techniques are used to study a two-electron system for which exact results can be obtained. The energy and single-particle density are calculated for the lowest singlet and triplet states. The results show that both methods give reasonable agreement with the exact answer. The path integral calculations also give the correlated two-electron wave functions, which compare favorable with the exact results. Finally, the exchange-correlation hole is evaluated from the path integral simulations. The study demonstrates that path integral calculations are as accurate as density functional calculations and yield additional information in the form of …