Isotope exchange reactions involving HCO⁺ with CO: A theoretical approach

¹ Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallée, France
e-mail: Mirjana.Mladenovic@u-pem.fr
² LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, 92190 Meudon, France
e-mail: evelyne.roueff@obspm.fr

Received: 29 May 2017
Accepted: 6 July 2017

Abstract

Aims. We aim to investigate fractionation reactions involved in the ¹²C/¹³C, ¹⁶O/¹⁸O, and ¹⁷O balance.

Methods. Full-dimensional rovibrational calculations were used to compute numerically exact rovibrational energies and thermal equilibrium conditions to derive the reaction rate coefficients. A nonlinear least-squares method was employed to represent the rate coefficients by analytic functions.

Results. New exothermicities are derived for 30 isotopic exchange reactions of HCO⁺ with CO. For each of the reactions, we provide the analytic three-parameter Arrhenius-Kooij formula for both the forward reaction and backward reaction rate coefficients, that can further be used in astrochemical kinetic models. Rotational constants derived here for the ¹⁷O containing forms of HCO⁺ may assist detection of these cations in outer space.