Chemical Processes in the Interstellar Medium

Part of the Physical Chemistry in Action book series (PCIA)


Models of the chemical composition of the interstellar medium incorporate networks of chemical reactions. The rate coefficients and the products of these reactions are important components of the model. In this chapter I review the determinants of these components and the methods used to measure them experimentally and calculate them using theory. The bulk of the chapter is devoted to ion + neutral molecule and neutral molecule + neutral molecule reactions. I also briefly discuss radiative association, dissociative recombination and reactions occurring on surfaces. The conditions of low pressure and low temperature in the interstellar medium place considerable demands on experiment and theory, which are particularly severe for reactions between neutral species. Many reactions can be estimated with tolerable accuracy. Others require a combination of high level electronic structure calculations, coupled with detailed theory and low temperature experimental measurements.


Transition State Rate Coefficient Phase Space Theory Variational Transition State Theory Master Equation Approach 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



I thank Dr. Stephen Klippenstein for helpful discussion of uncertainties in transition state energies in electronic structure calculations and Dr. Branko Ruscic for the provision of recent data for the Active Thermochemical Tables (ATcT).


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Authors and Affiliations

  1. 1.School of ChemistryUniversity of LeedsLeedsUK

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