Abstract
Isotopic fractionation in interstellar clouds can occur by ion-molecule reactions at low temperatures. The major effect is not kinetic but thermodynamic in origin in that it arises from the difference in rate coefficients between forward and backward directions in reactions which exchange isotopic atoms. In this article, we concentrate on deuterium fractionation in interstellar clouds; this effect enhances the relative abundances of deuterated isotopomers to their normal counterparts by up to four orders of magnitude as compared with the basic D/H elemental abundance ratio. We also discuss the fractionation of 15N and 13C.
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Herbst, E. (2003). Isotopic Fractionation by Ion-Molecule Reactions. In: Kallenbach, R., Encrenaz, T., Geiss, J., Mauersberger, K., Owen, T.C., Robert, F. (eds) Solar System History from Isotopic Signatures of Volatile Elements. Space Sciences Series of ISSI, vol 16. Springer, Dordrecht. https://doi.org/10.1007/978-94-010-0145-8_19
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DOI: https://doi.org/10.1007/978-94-010-0145-8_19
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