A NEW JASTROW FACTOR FOR ATOMS AND MOLECULES, USING 2-ELECTRON SYSTEMS AS A GUIDING PRINCIPLE

To get an idea of the qualitative behavior of an optimal Jastrow factor we have considered a Hylleraas-type wave function of very high accuracy for the helium atom. Owing to the lack of nodes this wave function can be easily interpreted as a general type of Jastrow factor. As a result we obtained a simple parameter dependent ansatz for a Jastrow factor, which incorporates the essential features of the observed behavior. We have optimized the parameters with respect to the variance of the local energy, using variational Monte Carlo techniques, for the atoms He through Ne and for the simple molecules H 2, LiH, and Li2. Finally, we compare our approach with other types of Jastrow factors discussed in the literature. © 1995 American Institute of Physics.