Some Remarks on the Semi‐ and the Nonempirical Values of the Slater‐Condon Parameters and the Parametrization for the One‐Center Electron Repulsion Integrals in the Semiempirical Molecular Orbital Method

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Abstract
The difference which is present between the semi‐ and the nonempirical value of a Slater‐Condon parameter (SCP) is discussed. It is pointed out that the nonempirical value which is to be compared with its semiempirical counterpart, must be determined with the same least‐squares method as that used in the determination of the semiempirical values, by treating the Hartree‐Fock (HF) total energy of each state of a configuration as the term value of the respective state, although it is usually determined for each of the states by a direct integration using the HF AO's appropriate to respective states. The data for the atoms and the ions having the electron configurations of 1s 22sm 2pn type show that the nonempirical value of an SCP thus determined for a particular configuration is more or less the same as that is obtained as the weighted mean of the values of the parameter determined for various states belonging to the configuration by integrations using HF AO's. The difference between the nonempirical value of an SCP thus obtained from the HF total energies and its semiempirical value obtained from the observed term values is analyzed with reference to the correlation energy of the atom in its various states of the configuration. Through this analysis, the semiempirical evaluation of the valence‐state energy of an atom is critically considered and prescriptions for obtaining the most appropriate values of the one‐center two‐electron repulsion integrals in the semiempirical molecular orbital theory are given.