# Rate Constants and Energetics of the H2SiO + H Reaction System: RP‐VTST/MT and VRC Calculations

## TL;DR

This study calculates the energy and reaction rates for the breakdown of silaformaldehyde in different chemical pathways.

## Contribution

The paper provides new accurate energetics and rate constants for H2SiO decomposition using advanced computational methods.

## Key findings

- At 500 K, H2SiOH is the main product of H2SiO decomposition.
- Bimolecular products H2 + HSiO dominate at higher temperatures.
- Electronic barrier heights for the three reactions were calculated as 4.5, 5.2, and 0.4 kcal mol−1.

## Abstract

Silaformaldehyde (H2SiO) is one of the components of the kinetics roadmap of silane oxidation. For this species, kinetics decomposition is related to three elementary reactions, that is, H + H2SiO → H2 + HSiO (R1), H + H2SiO → H2SiOH (R2), and H + H2SiO → H3SiO (R3). To improve the kinetics of these reaction systems, accurate energetics were computed with the ωB97X‐D and CCSD(T) methods, and the rate constants were determined using CVT methods with multidimensional tunneling. KIEs were also determined for (R1), which is an important path at high temperatures. At the ωB97X‐D/aug‐cc‐pVTZ level, the value of electronic barrier height is 4.5, 5.2, and 0.4 kcal mol−1 for (R1), (R2), and (R3), respectively. In addition to the characterization of the elementary reactions, a mechanism consisting of all interconnected reactions was characterized by using the energy‐grained master equation approach to determine the phenomenological rate constants for the formation of products and the time evolution of the species. Up to 500 K, the main reaction product is H2SiOH, while the bimolecular products H2 + HSiO dominate at higher temperatures.

The decomposition of Silaformaldehyde (H2SiO) involves three reactions: H + H2SiO → H2 + HSiO (R1), H + H2SiO → H2SiOH (R2), and H + H2SiO → H3SiO (R3). Accurate energetics were calculated using ωB97X‐D and CCSD(T), and rate constants using CVT methods with multidimensional tunneling. Product formation and species evolution were modeled using the master‐equation approach.