Scaled single-zeta basis set for use with a silicon effective potential: Generalized valence bond description of disilane

1981 ◽  
Vol 19 (1) ◽  
pp. 131-137 ◽  
Author(s):  
Jules W. Moskowitz ◽  
Sid Topiol ◽  
Lawrence C. Snyder ◽  
Mark A. Ratner
Keyword(s):  
Effective Potential ◽  
Valence Bond ◽  
Basis Set ◽  
Generalized Valence Bond

scholarly journals An Investigation into the Approximations Used in Wave Packet Molecular Dynamics for the Study of Warm Dense Matter

Plasma ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 294-308
Author(s):  
William A. Angermeier ◽  
Thomas G. White
Keyword(s):  
Molecular Dynamics ◽  
Wave Packet ◽  
Hydrogen Plasma ◽  
Valence Bond ◽  
Dense Matter ◽  
Basis Set ◽  
Warm Dense Matter ◽  
Scaling Parameters ◽  
Oppenheimer Approximation ◽  
Semi Empirical

Wave packet molecular dynamics (WPMD) has recently received a lot of attention as a computationally fast tool with which to study dynamical processes in warm dense matter beyond the Born–Oppenheimer approximation. These techniques, typically, employ many approximations to achieve computational efficiency while implementing semi-empirical scaling parameters to retain accuracy. We investigated three of the main approximations ubiquitous to WPMD: a restricted basis set, approximations to exchange, and the lack of correlation. We examined each of these approximations in regard to atomic and molecular hydrogen in addition to a dense hydrogen plasma. We found that the biggest improvement to WPMD comes from combining a two-Gaussian basis with a semi-empirical correction based on the valence-bond wave function. A single parameter scales this correction to match experimental pressures of dense hydrogen. Ultimately, we found that semi-empirical scaling parameters are necessary to correct for the main approximations in WPMD. However, reducing the scaling parameters for more ab-initio terms gives more accurate results and displays the underlying physics more readily.

scholarly journals Calculation of dispersion interactions with the geminal-based ring Coupled Cluster Doubles method

2020 ◽  
Vol 139 (9) ◽  
Author(s):  
Á. Margócsy ◽  
Á. Szabados
Keyword(s):  
Wave Function ◽  
Asymptotic Behaviour ◽  
Noble Gas ◽  
Valence Bond ◽  
Coupled Cluster ◽  
Leading Order ◽  
Dispersion Interactions ◽  
Dispersion Energy ◽  
Generalized Valence Bond ◽  
Noble Gas Dimers

Abstract The performance of the recently developed multi-reference extension of ring coupled cluster doubles is investigated for dispersion energy calculations, applied to the generalized valence bond wave function. The leading-order contribution to the dispersion energy is shown to have the correct asymptotic behaviour. Illustrative calculations on noble gas dimers are presented.

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