Interstellar Dust-Catalyzed Molecular Hydrogen Formation Enabled by Nuclear Quantum Effects

Fuente: arXiv
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Autori principali: Yang, Xiaolong, Wang, Lile, Li, Di, Xu, Shenzhen
Natura: Preprint
Pubblicazione: 2025
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author Yang, Xiaolong
Wang, Lile
Li, Di
Xu, Shenzhen
author_facet Yang, Xiaolong
Wang, Lile
Li, Di
Xu, Shenzhen
contents Molecular hydrogen (H$_2$) plays a critical role in astrophysical processes from galaxy evolution to the formation of planets. While the dominant formation channel in the interstellar medium is considered as dust-catalyzed H$_2$ formation, this process could become inefficient at low temperatures suppressed by the Boltzmann factor. This work demonstrates that quantum tunneling can dominate the formation of H$_2$, resolving the long-standing problem of formation efficiency. Path integral Monte Carlo simulations reveals that the quantum tunneling of hydrogen atoms maintains stable reaction rates at temperatures below 50 K on both graphitic and silicate grain surfaces. Kinetic Monte Carlo calculations further indicate that the actual H$_2$ formation efficiency is governed not by atomic diffusion, but rather by the energy barriers associated with chemisorption, desorption, and the association of two hydrogen atoms. These findings establish a robust physical basis for dust-catalyzed H$_2$ formation, offer quantitative reaction rates for refining astrophysical models, and provide a framework for interpreting observations of interstellar molecular materials.
format Preprint
id arxiv_https___arxiv_org_abs_2509_25070
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Interstellar Dust-Catalyzed Molecular Hydrogen Formation Enabled by Nuclear Quantum Effects
Yang, Xiaolong
Wang, Lile
Li, Di
Xu, Shenzhen
Astrophysics of Galaxies
Instrumentation and Methods for Astrophysics
Solar and Stellar Astrophysics
Chemical Physics
Molecular hydrogen (H$_2$) plays a critical role in astrophysical processes from galaxy evolution to the formation of planets. While the dominant formation channel in the interstellar medium is considered as dust-catalyzed H$_2$ formation, this process could become inefficient at low temperatures suppressed by the Boltzmann factor. This work demonstrates that quantum tunneling can dominate the formation of H$_2$, resolving the long-standing problem of formation efficiency. Path integral Monte Carlo simulations reveals that the quantum tunneling of hydrogen atoms maintains stable reaction rates at temperatures below 50 K on both graphitic and silicate grain surfaces. Kinetic Monte Carlo calculations further indicate that the actual H$_2$ formation efficiency is governed not by atomic diffusion, but rather by the energy barriers associated with chemisorption, desorption, and the association of two hydrogen atoms. These findings establish a robust physical basis for dust-catalyzed H$_2$ formation, offer quantitative reaction rates for refining astrophysical models, and provide a framework for interpreting observations of interstellar molecular materials.
title Interstellar Dust-Catalyzed Molecular Hydrogen Formation Enabled by Nuclear Quantum Effects
topic Astrophysics of Galaxies
Instrumentation and Methods for Astrophysics
Solar and Stellar Astrophysics
Chemical Physics
url https://arxiv.org/abs/2509.25070