Some H/D exchange reactions involved in the deuteration of interstellar molecules

Deuterium is commonly observed in interstellar molecules which vary in complexity from HD to CH3OD. Quantitative estimates of deuteration rates have been hampered by the lack of appropriate kinetic data and thermodynamic data. Experimental investigations have, therefore, been initiated of ion-molecule reactions in which isotope exchange occurs, including reactions involving H/D exchange. A major objective of such studies is to determine the temperature variation of reaction rate coefficients. The present investigation is mainly concerned with studies of the reaction D(+) + H2 yields reversibly H(+) + HD, which generates the interstellar HD, and with the reactions H3(+) + HD yields reversibly H2D(+) + H2, and CH3(+) + HD yields reversibly CH2D(+) + H2, which are both probably important first steps in the synthesis of deuterated molecules.