Why Hylleraas-type functions failed to predict the existence of PsLi(+) and (2,3)PsHe(+)?

摘要

The features of the simple wave functions with the correlation factors in the form of powers of r(12) leading to the incorrect description of the positronic systems are discussed. Comparison with the Gaussian correlation factor is carried out. The subject of the calculations are fictitious two-particle systems with fractional charge of the nucleus. In contrast, similar comparison has been performed for the helium atom, which serves as the example of the purely electronic system. The nonphysical effects: nodal hypersurfaces and "halo"-additional extrema of the wa iie function-have been found. Their presence is related to the form of the correlation factor, used in the function describing the positronic systems. (C) 2000 John Wiley & Sons, Lnc. Int J Quantum Chem 79: 243-252, 2000. [References: 35]