The Importance of Classes of Neutral-Neutral Reactions in the Production of Complex Interstellar Molecules

The role of classes of neutral-neutral reactions in the gas-phase synthesis of complex interstellar molecules is determined via a series of model calculations. Reactions between O or N atoms and bare carbon clusters C_n appear to be critical in hindering the synthesis of complex species. Neutral-neutral reactions involving molecular hydrogen that occur via tunneling under potential energy barriers are shown to aid molecular synthesis. We demonstrate that, despite the existence of rapid neutral-neutral reactions, large abundances of complex molecules can be produced in dense clouds.