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

Abstract

We discuss electronic properties and their evolution for the linear chain of H2 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. PACS numbers: 71.30.+h 71.27.+a 71.15.-m 31.15.A-, arXiv:1803.04855v1 [cond-mat.mtrl-sci]

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