Numerical self-consistent field method for polyatomic molecules

A method for non-relativistic self-consistent field (SCF) electronic struct ure calculations for polyatomic molecules is described, which retains the l inear combination of atomic orbitals ansatz for molecular orbitals (MO-LCAO ), but replaces the usual algebraic expansion of atom-centred radial parts in terms of basis functions (usually some kind of Gauss-type functions) by a numerical representation on a set of radial grid points around each centr e. The radial parts are optimized, according to the variation principle, un til self-consistency is achieved. Even though Fourier integral transform te chniques are used the method works completely in ordinary space. Intermedia te quantities defined in momentum space are evaluated in closed form.