Analysis of long range dispersion and exchange interactions between two K atoms.

This paper critically surveys the best available spectroscopic data for the two lowest electronic states (X 1Σ+g and a 3Σ+u) of K2. Since both states are known up to dissociation, they can be used to determine Coulomb and exchange contributions to the intermediate and long range interaction potentials. The multipolar expansion representation of the Coulomb (dispersion) energy at long range (-ΣnCnR-n) and the exponential representation of the exchange energy (Ae-αR) as well as a variety of theoretical calculations are compared with these empirical results. Finally, dissociation energy values are discussed and improved dissociation energies for the X 1Σ+g (De=4449.1±1.0 cm-1) and the a 3Σ+u state (De=252.9±1.1 cm-1) proposed. © 1994 American Institute of Physics. [ABSTRACT FROM AUTHOR]