title: Fixed-node diffusion Monte Carlo study of the structures of m-benzyne.
abstract: Diffusion Monte Carlo (DMC) calculations are performed on the monocyclic and bicyclic forms of m-benzyne, which are the equilibrium structures at the CCSD(T) and CCSD levels of coupled cluster theory. We employed multiconfiguration self-consistent field trial wave functions which are constructed from a carefully selected eight-electrons-in-eight-orbitals complete active space [CAS(8,8)], with configuration state function coefficients that are reoptimized in the presence of a Jastrow factor. The DMC calculations show that the monocyclic structure is lower in energy than the bicyclic structure by 1.9(2) kcal/mole, which is in excellent agreement with the best coupled cluster results.
authors.affiliation: Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853, USA. al-saidi@cornell.edu
authors.forename: W A
authors.initials: WA
authors.lastname: Al-Saidi
authors.forename: C J
authors.initials: CJ
authors.lastname: Umrigar