THE IMPORTANCE OF CHEMICAL-DATA FOR THE STUDY OF INTERSTELLAR SHOCKS

Shock waves perturb the chemical state of the interstellar gas. We con sider the effects of C-shocks on the composition of molecular clouds, for a range of values of the pre-shock gas density and magnetic induct ion. The time required to re-establish equilibrium in the post-shock g as depends on the initial conditions and can become very large. The si gnificance of the two known chemical phases of dark clouds and of bist ability is considered in this context.