Single-Center Molecular Wave Functions

Abstract

Publisher Summary This chapter discusses single-center molecular wave functions. It discusses method of calculation for simple wave functions and complex wave functions. By simple, it is meant that the wave function is a single determinant composed of just one atomic orbital for each electron. The simple wave function can be improved by using a single determinant and determining the one-electron atomic orbitals by numerical techniques (the Hartree-Fock procedure) or by replacing each atomic orbital with a linear combination of Slater-type orbitals. Either of these methods will produce an energy whose lower bound is the Hartree-Fock energy. Alternatively, the single determinant of the last section may be replaced by a linear combination of determinants, and if these determinants differ in more than one atomic orbital, it will be possible to obtain an energy lower than the Hartree-Fock energy, as some correlation energy will be included. Many properties are well accounted for by a single-center wave function composed of a limited number of terms and in some cases by a wave function, which is just a single term. Such properties are the bond distances, ionization potentials, breathing force constants, X-ray scattering factors, and relative energies.