An orbital-free self-consistent field approach for molecular clusters and liquids

TL;DR

This paper introduces an orbital-free density functional theory combining Bohm hydrodynamics and Bayesian analysis to efficiently compute quantum ground states of atomic clusters and liquids, demonstrated on Argon clusters.

Contribution

It develops a novel orbital-free quantum simulation method integrating hydrodynamics and statistical inference, enabling efficient ground state calculations for clusters and liquids.

Findings

Successfully computed ground state structures of Argon clusters.

Demonstrated the method's applicability to small rare-gas clusters.

Framework is extendable to larger many-atom systems.

Abstract

We present an ``orbital'' free density functional theory for computing the quantum ground state of atomic clusters and liquids. Our approach combines the Bohm hydrodynamical description of quantum mechanics with an information theoretical approach to determine an optimal quantum density function in terms of density approximates to a statistical sample. The ideas of Bayesian statistical analysis and an expectation-maximization procedure are combined to develop approximations to the quantum density and thus find the approximate quantum force. The quantum force is then combined with a Lennard-Jones force to simulate clusters of Argon atoms and to obtain the ground state configurations and energies. As demonstration of the utility and flexibility of the approach, we compute the lowest energy structures for small rare-glass clusters. Extensions to many atom systems is straightforward.