Exponentially correlated Gaussian functions in variational calculations. Momentum space properties of the ground state helium dimer

Microhartree accuracy wave functions composed of exponentially correlated Gaussians were transformed in closed form to momentum space representation and applied to compute various isotropic momentum space properties of helium dimer in the ground state. The set of properties includes electron momentum density distribution, expectation values of powers of the electronic momentum operator, and the Compton profile. Calculations were performed at many internuclear separations R including the united atom (beryllium) and the separated atoms (helium) limits. (C) 2001 American Institute of Physics.