Atomization of correlated molecular-hydrogen chain: A fully microscopic Variational Monte-Carlo solution

TL;DR

This paper employs a microscopic Variational Monte Carlo approach to study the electronic properties and dissociation behavior of a correlated hydrogen chain under external force, providing detailed insights into molecular-to-atomic transition mechanisms.

Contribution

It introduces a fully microscopic VMC method combined with ab initio parameters to analyze the evolution and dissociation of a correlated hydrogen chain under external force.

Findings

Detailed analysis of the molecular-to-atomic transition.

Systematic study of Peierls distortion stability.

Estimation of the VMC approach's reliability.

Abstract

We discuss electronic properties and their evolution for the linear chain of $H_2$ molecules in the presence of a uniform external force $f$ acting along the chain. The system is described by an extended Hubbard model within a fully microscopic approach. Explicitly, the microscopic parameters describing the intra- and inter-site Coulomb interactions are determined together with the hopping integrals by optimizing the system ground state energy and the single-particle wave functions in the correlated state. The many-body wave function is taken in the Jastrow form and the Variational Monte-Carlo (VMC) method is used in combination with an ab initio approach to determine the energy. Both the effective Bohr radii of the renormalized single-particle wave functions and the many-body wave function parameters are determined for each $f$. Hence, the evolution of the system can be analyzed in detail as a function of the equilibrium intermolecular distance, which in turn is determined for each $f$ value. The transition to the atomic state, including the Peierls distortion stability, can thus be studied in a systematic manner, particularly near the threshold of the dissociation of the molecular into atomic chain. The computational reliability of VMC approach is also estimated.