Methyl radicals dynamics on (100)--(2x1):H diamond surfaces based on refined variational transition state calculations of gas-surface reaction rate coefficients
Abstract
Theoretical modelling of diamond growth should ideally provide estimates of the growth rate depending on experimental conditions. To that end, a description of all possible reactions related to the competing adsorption, desorption and migration mechanisms is required. Here, we provide precise calculations of the reaction rate coefficient of methyl-related reactions on hydrogen-terminated (100) diamond surface, as CH3 is known to be the main growth precursor in chemical vapor deposition (CVD) growth of diamond. To achieve this goal, we successfully combined Density Functional Theory (DFT) and variational transition state theory (VTST), allowing to extend our analysis to barrierless reaction. Our rigorous treatment of the quasi-free rotation of CH3 adsorbates on the surface allows us to overcome numerical errors for the finite difference calculations of the vibrational spectra for evaluating the partition functions of the system. Our results suggest that the mechanism that deplete the CH3 concentration the most is the absorption on a surface radical site. We also evidence the anisotropy of CH3 migration along the dimer of the (100)-(2x1):H surface. In a more general perspective, the calculated reaction rates coefficient for methyl reactions and migration presented in this work, together with the data for hydrogen reaction and other main gas surface reactions, bridge the gap between the atomic-scale description and the large-scale modelling of diamond growth.
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BibTeX
@misc{guillaume2026methyl,
title = {{Methyl radicals dynamics on (100)--(2x1):H diamond surfaces based on refined variational transition state calculations of gas-surface reaction rate coefficients}},
author = {Emerick Y. Guillaume and Luc Henrard and Ken Haenen and Danny E. P. Vanpoucke},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.34584},
eprint = {2610.34584},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.34584},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - Methyl radicals dynamics on (100)--(2x1):H diamond surfaces based on refined variational transition state calculations of gas-surface reaction rate coefficients
AU - Emerick Y. Guillaume
AU - Luc Henrard
AU - Ken Haenen
AU - Danny E. P. Vanpoucke
PY - 2026
DA - 2026/10/25
PB - arXiv
DO - 10.48550/arxiv.2610.34584
UR - https://arxiv.org/abs/2610.34584
AB - Theoretical modelling of diamond growth should ideally provide estimates of the growth rate depending on experimental conditions. To that end, a description of all possible reactions related to the competing adsorption, desorption and migration mechanisms is required. Here, we provide precise calculations of the reaction rate coefficient of methyl-related reactions on hydrogen-terminated (100) diamond surface, as CH_3 is known to be the main growth precursor in chemical vapor deposition (CVD) growth of diamond. To achieve this goal, we successfully combined Density Functional Theory (DFT) and variational transition state theory (VTST), allowing to extend our analysis to barrierless reaction. Our rigorous treatment of the quasi-free rotation of CH_3 adsorbates on the surface allows us to overcome numerical errors for the finite difference calculations of the vibrational spectra for evaluating the partition functions of the system. Our results suggest that the mechanism that deplete the CH_3 concentration the most is the absorption on a surface radical site. We also evidence the anisotropy of CH_3 migration along the dimer of the (100)-(2x1):H surface. In a more general perspective, the calculated reaction rates coefficient for methyl reactions and migration presented in this work, together with the data for hydrogen reaction and other main gas surface reactions, bridge the gap between the atomic-scale description and the large-scale modelling of diamond growth.
ER -