Best optimized one-electron wave functions. I. The general procedure of optimization

A new effective semiempirical method of optimization of one-electron wave functions was proposed without a necessity to determine any exact many-electron wave function. The method designed for LCAO MO calculations is based on a concept of interacting quasi-particles and on nonorthogonal spin-orbitals. ''Mixing'' of the pure single-particle wave functions is optimized by means of the procedure which requires only one empirical parameter for each considered state of a whole system. The procedure results in optimal distribution of total electron charge between the individual spin-orbitals. The general method was illustrated with calculations for the ground state of lithium atom