Orbital Valency

The interaction of two atoms, each with one 2p electron, is studied by a method similar to that used by Kemble and Zener. An atomic wave function whose radial part is of the form const. re^-kr{2} (that is, with no nodes) is used. Complete potential energy curves are obtained for the twelve possible states, which are ^1₆, ^3ₔ, ^1₆, ^1ₔ, ^3₆, ^3ₔ, ^1ₔ^-, ^3₆^-, two ^1₆^+, and two ^3ₔ^+. The most stable states are ^3ₔ^+ (lowest) and ^1₆^+, which arise from m₋^{a}=0 and m₋^{b}=0, and in which there is the maximum overlapping of charge. The states with least overlapping of charge are those where m₋^{a}=1 and m₋^{b}=1, resulting in ^1₆, ^3ₔ, ^1₆^+, ^1ₔ^-, ^3₆^-, ^3ₔ^+, which are all repulsive. The II states lie in between, and are attractive. The present work gives precision to the ideas of Heitler on orbital valency, yields a positive exchange energy integral for the lowest states, and may be taken as supporting the conceptions of Slater about directed valency.