Lone-pair and core ionization potentials of planar ammonia and phosphine. The use of core and valence ionization potentials to quantify the bonding and antibonding character of molecular orbitals of compounds of nitrogen and phosphorus

For both ammonia and phosphine, the differences between the ionization potentials of the pyramidal and planar forms were calculated by an ab initio self-consistent field SCF method. The lone-pair ionization potential differences, IP(planar)-IP(pyramidal), are -1.0 and -2.3 eV for NH/sub 3/ and PH/sub 3/, respectively.The core binding energy shifts, E/sub B/(planar)-E/sub B/(pyramidal), are -0.3 and -0.4 eV for PH/sub 3/, respectively. By combining these data with appropriate experimental valence and core ionization potentials, it is possible to quantify the bonding or antibonding character of molecular orbitals of nitrogen and phosphorus compounds. The method is illustrated by using data for several nitrogen- and phosphorus-containing species. 4 tables.