Encyclopedia of Astrobiology

2015 Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James (Jim) CleavesII, Daniele L. Pinti, José Cernicharo Quintanilla, Daniel Rouan, Tilman Spohn, Stéphane Tirard, Michel Viso

Reaction Rate Coefficient

Reference work entry
DOI: https://doi.org/10.1007/978-3-662-44185-5_1350

Definition

Reaction rate coefficients are the phenomenological coefficients occurring in rate expressions for elementary chemical reactions. They can be determined either experimentally or theoretically. Bimolecular rate coefficients are expressed in units of cm3 s−1 and unimolecular ones in units of mol. s−1. Typical values for interstellar chemistry are 10−9 cm3 s−1 for ion-neutral reactions and 10−11 cm3 s−1 for neutral-neutral reactions.

For example, for the reaction
$$ \mathrm{A}+\mathrm{B}\to \mathrm{C}+\mathrm{D}, $$
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Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  1. 1.Solar System Exploration Division, Code 691, Astrochemistry LaboratoryNASA Goddard Space Flight CenterGreenbeltUSA