Fock expansion coefficient representation

Expansion coefficients and Gaussian exponents for 3-2IG and 6-31G representations have been determined by Hartree-Fock energy minimization on atomic ground states. In the case of 6-3IIG representations, minimizations have been carried out at the MP2 level rather than at the Hartree-Fock level. 

The problem is now solved again by an iterative process, which starts with a choice of the x set and the expansion (6.58). The Hartree-Fock operator F and the matrix representation Fx are calculated, (6.64) is solved for the orbital energies, and these are used to compute a new set of coefficients in (6.63). If these are different from the starting set, the cycle is repeated until the self-consistent-field limit is reached. The total electronic energy is obtained by adding the SCF energy to the core energy for the lowest occupied n/2 levels ... 

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