We present a novel chemical database for gas-phase astrochemistry. Named the KInetic Database for Astrochemistry (KIDA), this database consists of gas-phase reactions with rate coefficients and uncertainties that will be vetted to the greatest extent possible. Submissions of measured and calculated rate coefficients are welcome, and will be studied by experts before inclusion into the database. Besides providing kinetic information for the interstellar medium, KIDA is planned to contain such data for planetary atmospheres and for circumstellar envelopes. Each year, a subset of the reactions in the database (kida.uva) will be provided as a network for the simulation of the chemistry of dense interstellar clouds with temperatures between 10 K and 300 K. We also provide a code, named Nahoon, to study the timedependent gas-phase chemistry of 0D and 1D interstellar sources.

There is now ample evidence from an assortment of experiments, especially those involving the CRESU (Cinétique de Réaction en Ecoulement Supersonique Uniforme) technique, that a variety of neutral–neutral reactions possess no activation energy barrier and are quite rapid at very low temperatures. These reactions include both radical–radical systems and, more surprisingly, systems involving an atom or a radical and one ‘stable’ species. Generalizing from the small but growing number of systems studied in the laboratory, we estimate reaction rate coefficients for a larger number of such reactions and include these estimates in a new network of gas‐phase reactions for use in low‐temperature interstellar chemistry. Designated osu.2003, the new network is available on the World Wide Web and will be continually updated. A table of new results for molecular abundances in the dark cloud TMC‐1 (CP) is provided and compared with results from an older (new standard model; nsm) network.

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Because of their importance in atmospheric and combustion chemistry, the rate coefficients and mechanisms of gas-phase reactions of the OH radical have been studied extensively, and the kinetic database for these reactions is unsurpassed. The OH radical has a rather large electric dipole moment (1.668 D) and is clearly capable of forming strong hydrogen bonds. In this article, we examine the evidence for the importance of such interactions in reactions of OH. We propose that the reactions of OH with alkanes and with HNO 3 represent extremes of behavior, with no effect of hydrogen bonding in the first case but reaction via a rather strongly bound intermediate complex in the second. From this base, we go on to discuss, in turn, the reactions of OH with carboxylic acids, aldehydes, ketones, hydrogen halides, and CO, with the emphasis on the possible role of hydrogen bonding between the reagents of these reactions.