Assessing many-body methods on the potential energy surface of the (H${}_2$)${}_2$ hydrogen dimer

Abstract

The anisotropic potential energy surface of the (H${}_2$)${}_2$ dimer represents a challenging problem for many-body methods. Here, we determine the potential energy curves of five different dimer configurations (T, Z, X, H, L) using the lattice regularized diffusion Monte Carlo (LRDMC) method and a number of approximate functionals within density functional theory (DFT), including advanced orbital-dependent functionals based on the random phase approximation (RPA). We assess their performance in describing the potential wells, bond distances and relative energies. The repulsive potential wall is studied by looking at the relative stability of the different dimer configurations as a function of an applied force acting along the intermolecular axis. It is shown that most functionals within DFT break down at finite compression, even those that give an accurate description around the potential well minima. Only by including exchange within RPA a qualitatively correct description along the entire potential energy curve is obtained. Finally, we discuss these results in the context of solid molecular hydrogen at finite pressures.

25 pages, 15 figures

References in corpus (12)

• Advanced capabilities for materials modelling with Quantum ESPRESSO
• A Higher-Accuracy van der Waals Density Functional
• Efficient and accurate calculation of exact exchange and RPA correlation energies in the Adiabatic-Connection Fluctuation-Dissipation theory
• Range-separated density-functional theory with random phase approximation applied to noncovalent intermolecular interactions
• A six-dimensional H2-H2 potential energy surface for bound state spectroscopy
• Resonating valence bond wave function with molecular orbitals: Application to first-row molecules
• Towards a formal definition of static and dynamic electronic correlations
• Static and dynamical correlation in diradical molecules by Quantum Monte Carlo using the Jastrow Antisymmetrized Geminal Power ansatz
• Correlation energy within exact-exchange ACFD theory: systematic development and simple approximations
• Trial wave functions for High-Pressure Metallic Hydrogen
• A comparative study using state-of-the-art electronic structure theories on solid hydrogen phases under high pressures
• Assessing the Accuracy of the Jastrow Antisymmetrized Geminal Power in the H4 Model System