D. Bressanini et al., MANY-ELECTRON CORRELATED EXPONENTIAL WAVE-FUNCTIONS - A QUANTUM MONTE-CARLO APPLICATION TO H-2 AND HE-2(+), Chemical physics letters, 240(5-6), 1995, pp. 566-570
We propose to expand the solution of the Schrodinger equation for an a
tomic or molecular system as a linear combination of many-electron exp
licitly correlated exponentials. A series of trial wavefunctions has b
een optimized, minimizing the variance of the local energy for H-2 and
He-2(+) in their ground state at the equilibrium distance, and their
variational energy has been computed using the variational Monte Carlo
method. The He-2(+) wavefunctions have been used in a series of fixed
node diffusion Monte Carlo simulations, showing that, using a small n
umber of terms, one can obtain a good estimate of the exact energy.