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An Investigation Into the Approximations Used in Wave Packet Molecular Dynamics for the Study of Warm Dense Matter by Angermeier, William A.; White, Thomas G. is a scholarly article available to read on EtoBox.

What is An Investigation Into the Approximations Used in Wave Packet Molecular Dynamics for the Study of Warm Dense Matter about?

Wave packet molecular dynamics (WPMD) has recently received a lot of attention as a computationally fast tool 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 investigate three of the main approximations ubiquitous to WPMD: a restricted basis set, approximations to exchange, and the lack of correlation. We examine each of these approximations in atomic and molecular hydrogen in addition to a dense hydrogen plasma. We find 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 find 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.

Author

Angermeier, William A.; White, Thomas G.

Published

2021

Language

EN