OPTICAL-TRANSITIONS IN EXCITED ALKALI PLUS RARE-GAS COLLISION MOLECULES AND RELATED INTERATOMIC POTENTIALS - LI-ASTERISK-NE

Theoretical and experimental collision induced spectra associated with the transitions 2P Lambda --> 3D Lambda, 3P Lambda* as well as 3S Si gma --> 2S Sigma in LiNe are compared. By means of quantum mechanical simulations, using new ab initio (AI) and semiempirical (MP) potentia ls and transition moment functions, the contributions from free-free a nd bound-free transitions on the individual molecular channels to the spectra are analysed and the accuracy of the potentials is tested. In particular, from the excitation spectra 2P Lambda --> 3D Sigma measure d with absolute intensity scaling, the experimental 3D Sigma potential in the barrier region 8-15 a(0) is obtained by inversion. It is found that the barrier parameters of the Al method reproduce the experiment al values within error limits, whereas the barrier height from the MP approach is off by about 100 cm(-1). Beyond the barrier maximum the th eoretical energies decrease faster than the experimental ones. The exp erimental 3S Sigma --> 2S Sigma spectrum is well reproduced by the cal culations with the AI data set, showing that the latter are accurate w ithin their limits of confidence.