title: Quantum Monte Carlo with density matrix: potential energy curve derived properties.
abstract: In this work, we used diffusion quantum Monte Carlo with density matrix (d-DMC) and variational quantum Monte Carlo (d-VMC) to determine the potential energy curve (PEC) and obtain the spectroscopic constants of H2molecule in the ground state, in order to evaluate the capability of these methods to provide an accurate PEC description. These quantum Monte Carlo methods build with density matrix are new approaches to conventional quantum Monte Carlo methods based on wave function formed by product of α and β determinants. To investigate the robustness of d-DMC, we performed calculations with two different basis sets and analyzed the influence of the size of these sets on results. To the best of our knowledge, this is the first study that shows the dissociation energy and rotational constant obtained from d-QMC. We found that the quality of PEC described by the d-DMC is essentially coincident with the most accurate results available in the literature, regardless of the complexity of basis set employed.
authors.affiliation: Instituto de Química, Universidade de Brasília, 70904-970, CP 4478, Brasília, DF, Brazil.
authors.forename: Víctor S
authors.initials: VS
authors.lastname: Bonfim
authors.affiliation: Instituto de Física, Universidade de Brasília, 70904-970, CP 4455, Brasília, DF, Brazil.
authors.forename: Nádia M
authors.initials: NM
authors.lastname: Borges
authors.affiliation: Instituto de Química, Universidade de Brasília, 70904-970, CP 4478, Brasília, DF, Brazil.
authors.forename: João B L
authors.initials: JB
authors.lastname: Martins
authors.affiliation: Instituto de Física, Universidade de Brasília, 70904-970, CP 4455, Brasília, DF, Brazil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Gargano
authors.affiliation: Instituto de Química, Universidade de Brasília, 70904-970, CP 4478, Brasília, DF, Brazil. politi@unb.br.
authors.forename: José Roberto Dos S
authors.identifier: http://orcid.org/0000-0001-8202-6586
authors.initials: JR
authors.lastname: Politi
keywords: DVR; Density matrix; Potential energy curve; Quantum Monte Carlo