Random tempering of Gaussian-type geminals. I. Atomic systems

Abstract
We use a method inspired by Monte Carlo quadrature formulas to create a basis set of Gaussian-type geminals for the calculation of the second-order energy of the beryllium atom. This technique matches results obtained by the full optimization of all nonlinear parameters but requires considerably less computational effort. For calculations involving microhartree accuracy this reduction may be as much as a factor of 1000.