Volume 113, Issue 9, 01 September 2000
Index of content:
113(2000); http://dx.doi.org/10.1063/1.1289526View Description Hide Description
We have investigated the reaction on the Stark–Werner potential energy surface using quantum scattering theory, adiabatic theory, and spectral quantization. Clear evidence is found for a transition state resonance on this potential surface. Comparison to experimental results suggests that a resonance is also present in the true reaction.
113(2000); http://dx.doi.org/10.1063/1.1289918View Description Hide Description
We present a method for evaluating Coulomb interactions in periodic molecular systems. The real space term in Ewald summation is accelerated using a tree code in which interactions between clusters and distant particles are approximated by multipole expansions. The performance is reported for water systems.
Estimating the overlap of an approximate with the exact wave function by quantum Monte Carlo methods113(2000); http://dx.doi.org/10.1063/1.1290009View Description Hide Description
This work is an extension of Langfelder, Rothstein, and Vrbik’s [J. Chem. Phys. 107, 8525 (1997), (LRV)] algorithm that samples the “exact” ground state distribution The distribution is the same as that obtained from exactly solving the Schrödinger equation, but with a small error due to the incorrect nodes imposed on the simulation by the guiding function [J. B. Anderson, J. Chem. Phys. 65, 4121 (1976)] LRV applied their algorithm to estimate the expectation values of nondifferential properties for first-row atoms and ions. Our objective is to show that at the same time, with some relatively trivial modifications, the algorithm can estimate the overlap integral of with the exact wave function
113(2000); http://dx.doi.org/10.1063/1.1289919View Description Hide Description
Dielectric relaxation times of supercritical SPC/E water from molecular dynamics simulations are found to be in good agreement with recent experimental data for densities but the sharp increase in the experimental Debye time as decreases is not reproduced. Large discrepancies between experimental and simulation data in the dilute regime strongly suggest the need for additional measurements and/or theoretical work.