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

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