Cis--Trans Rotational Isomerism of Seleno-, Thio-, and Formic Acids and Their Dimers: Chemical Kinetics under Interstellar Conditions

TL;DR

This study provides kinetic rate constants for cis-trans isomerization of seleno-, thio-, and formic acids and their dimers across a temperature range, aiding understanding of interstellar chemistry on ice grains.

Contribution

It offers new multidimensional gas-phase calculations of isomerization rates for these acids, relevant to interstellar matrix reactions.

Findings

Rate constants vary significantly from 10 K to 300 K.

Data supports understanding of interstellar ice-grain chemistry.

Reveals tunnelling effects in low-temperature reactions.

Abstract

Tunnelling reactions of molecules embedded on cryogenic noble-gas matrices are being used in fundamental studies of how reactivity varies with the nature of the supposedly inert matrix as well as pointers to the chemistry occurring in the interstellar medium on ice-grains. To these ends we present chemical kinetic rate constants for the \textit{cis} to \textit{trans} isomerisation of seleno-, thio- and monomeric formic acids and that of their three dimeric species, based on multidimensional calculations in the gas-phase, from 10~K to 300~K as a guide to the matrix reactions.