Exploring the reaction channels between arsine and the hydroxyl radical

ABSTRACT

The aim of this study was to present the reaction mechanism channels between arsine (AsH₃) and hydroxyl (OH) which was evaluated at CCSD(T)/CBS//CCSD/cc-pVTZ level. One potential channel is the hydrogen abstraction pathway (R1), leading to AsH₂ and H₂O products, which occurs due to the formation of an entrance complex (AsH₃OH) followed by a 1,2-hydrogen shift pathway (involving the proton transfer from the arsine group to hydroxyls, with one leading to the products). Additional channels are accessed via H-elimination pathways of the entrance complexes, forming arsinous acid (AsH₂OH; R2) and arsine oxide (AsH₃O; R3). In this respect, R2 is the only exoergic route of the three exit channels, representing the major branching ratio at 200–1000 K and, after 2000 K, R1 increases gradually becoming the major route of this reaction. In contrast, even at 4000 K, R3 is a highly unfeasible pathway. Therefore, the information predicted here provides new insights into the neutral–neutral chemical reaction dynamics regarding the Group V hydrides. On the other side, the R2 pathway may have some potential to solve the arsine oxidation puzzle as a possible primary pathway to the arsenic-oxygen species formation.

KEYWORDS:

• Oxidation
• disequilibrium species
• giant planet atmosphere
• interstellar

Acknowledgments

The author wishes to thank CAPES for the research fellowship and to the Center for Scientific Computing (NCC/GridUNESP) of the São Paulo State University (UNESP) for providing the computational facilities.

Disclosure statement

No potential conflict of interest was reported by the author.

Additional information

Funding

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).