An investigation of the effect of a centrifugal barrier on proposed large rate coefficients for ion-polar neutral reactions at low temperatures

Recently, Adams, Smith, and Clary have proposed that ion-molecule rate coefficients as large as 10 -7 cm3 s-1 should be used in gas-phase models of interstellar clouds for reactions involving strongly polar neutral molecules. Rate coefficients this large involve collisions with large amounts of relative angular momentum, raising the possibility of short-range centrifugal barriers to reaction. In this paper, the effect of centrifugal barriers is investigated for a specific type of potential surface and found to be important only for reactions that are slow at room temperature.