THE EFFECT OF RAPID NEUTRAL-NEUTRAL REACTIONS ON CHEMICAL-MODELS OF DENSE INTERSTELLAR CLOUDS

Recent experiments on rapid neutral-neutral reactions involving the ra dical CN at low temperature and the neutral C atom at room temperature suggest that atom-neutral and radical-neutral reactions may be genera lly more rapid at low temperature than hitherto thought. We have inclu ded a variety of rapid neutral-neutral reactions in our gas-phase chem ical models of quiescent, dense interstellar clouds. We find the calcu lated abundances of many molecules to be greatly changed from previous values. In particular, the peak 'early-time' abundances of organic mo lecules are reduced.