ABSOLUTE RADIATIVE TRANSITION PROBABILITIES AND LIFETIMES INVOLVING THE $X^{1}\Sigma^{+}, A^{1}\sigma^{+}$ AND $B^{1}\Pi$ STATES OF $^{7}LiH$

This research was supported by the United States Department of Energy [Contract EY-76-S-02-2326.$^{*}$ 001].Author Institution: Department of Chemistry, Wartburg College; Departments of Chemistry and Physics, University of IowaUsing accurate hybrid potential energy curves (the construction of which was made possible by the accurate dissociation limits determined by Velasco and coworkers) and ab initio transition moment functions, we have calculated absolute radiative transition probabilities for all vibrational levels of all electronic band systems involving the $X^{1} \Sigma^{+}, A^{1} \Sigma^{+}$ and $B^{1} \Pi$ states of the $^{7}LiH$ molecule ($J^{\prime} = J^{\prime\prime} = 0$ only). We are in the process of calculating all bound-free and free-bound electronic transitions among these same electronic states as well. We have related these intensity calculations to the classical turning points of the vibrational levels involved in a given transition to discuss more physically the relative intensities of the various transitions. The relative transition probabilities are found to be in good overall agreement with the experiments of Velasco and coworkers and those in our laboratory, but with some interesting discrepancies. Using both bound $\rightarrow$ bound and bound $\rightarrow$ free emission probabilities, we have calculated the radiative lifetimes of all vibrational levels of the $A^{1} \Sigma^{+}$ and $B^{1} \Pi$ states of $^{7}LiH$. The $A^{1} \Sigma^{+}$ lifetimes are in excellent agreement with recent lifetime measurements. The $B^{1} \Pi$ levels show a strong increase in lifetime with vibrational quantum number (we calculate for v = 0, 1 and 2 lifetimes of 11.3, 17.0 and 24.0 nsec)