Electronic Structure of the First Row Hydrides

Abstract

Stehn's formulae for the energies of the first row hydrides, BH to FH, in terms of Heitler‐London exchange integrals have been applied to more recent data. The empirically derived values for the integrals are now smooth functions of the atomic number, Z. They are also considered as functions of the internuclear distance, r_e, and taken in conjunction with data on BeH, and with the facts that r_e and the force‐constant, k, are smooth functions of Z, but invariant to electronic excitation, the results show that it is 2s²—1s exchange that predominates in fixing the internuclear distance and force‐constant. On the contrary, the dissociation energies cannot be expected to be smoothly dependent on Z, r_e or k. The heat of dissociation of NH is calculated by Stehn's formulae, after interpolating one exchange integral.