A technique for orbital exponent optimization in ab initio HFSCFLCAOMO calculations

Abstract

AbstractA technique for Slater orbital exponent optimization in an HFSCFLCAOMO calculation is proposed in which orbital exponent variation is incorporated into the SCF scheme. This is accomplished by rewriting Slater's rules so that the shielding terms depend on the molecular charge distribution through the elements of the population matrix. The SCF scheme then includes a calculation of a new set of orbital exponents from the coefficients of self‐consistent molecular orbitals obtained from the previous set of exponents. The process is iterated until the energy attains its lowest value.The technique is illustrated by minimal basis calculations on LiH, BH, and HF. Near optimization is obtained with considerably less effort than is necessary for other reported techniques. Aside from interesting properties, the technique can be important for extended basis calculations where exponent optimization is a difficult task.