Spin–orbit interactions, new spectral data, and deperturbation

We report calculations of the spin–orbit energy as a function of internuclear distance R within the b )u state of K2 , and between the b )0u and A (u 1 states, together with new spectroscopic data on the b state and previously unpublished data on the A state. Both the new data and previous data are fitted to Hamiltonian parameters using the discrete variable representation ~DVR! method. The DVR matrix includes nonrelativistic Born–Oppenheimer potentials and spin–orbit interactions, which are scaled to match the known asymptotic limits and to best fit the experimental data. We report fitted Dunham coefficients that yield the A and b state potentials by means of the Rydberg– Klein–Rees method. These parameters thus take into account second-order spin–orbit perturbation shifts ~from the vibrational levels of these two states! which are normally not considered in band-by-band fits to spectroscopic data. © 2002 American Institute of Physics. @DOI: 10.1063/1.1522716#