Knowledge Bank

Multiconfiguration self-consistent-field (MCSCF) calculations have been carried out on the $X1\Sigma g+$ and $A1\Sigma u+$ states of $Na2$. The calculated potential energy curves are in good agreement with the experimental RKR curves of Hessel and Kusch. The $A\to X$ transition moment has been calculated as a function of nuclear separation using the MCSCF wavefunctions. A least squares fit to a cubic polynomial provides an analytic representation that is accurate to within 0.1 debye between 4.5 and 12.0 bohrs. The expansion coefficients are $C0=0.75784,C1=2.11363,C2=-0.10619,C3=-0.00079$, where $\mu$ is in debyes and the nuclear separation is in bhors (1 bohr = 5.291772 nm). Lifetimes for the $A\to X$ transition have been calculated using the theoretical transition moment and the experimental potential curves of Hessel and Kusch.