NON-LTE EXCITATION OF H-2 IN MAGNETIZED MOLECULAR SHOCKS

The observed H-2 line ratios in OMC-1 and IC 443 are not satisfactoril y explained by conventional shock excitation models. We consider the m icroscopic collisional processes implicit in ambipolar diffusion model s of magnetized C-shocks, and show that non-LTE level populations and emission-line ratios are an inevitable consequence of such models. Thi s has important implications for the use of molecular hydrogen lines a s diagnostics of shock models in molecular clouds.