Direct Determination of the Activation Energy for Diffusion of OH Radicals on Water Ice

Miyazaki A.; Tsuge M.; Hidaka H.; Nakai Y.; Watanabe N.

Title	en Direct Determination of the Activation Energy for Diffusion of OH Radicals on Water Ice
Creator	en Miyazaki, A. en Tsuge, M. en Hidaka, H. en Nakai, Y. en Watanabe, N. NRID 1000050271531
Accessrights	metadata only access
Subject	NDC 420
Description	Abstract en Using a combination of photostimulated desorption and resonance-enhanced multiphoton ionization methods, the behaviors of OH radicals on the surface of an interstellar ice analog were monitored at temperatures between 54 and 80 K. The OH number density on the surface of ultraviolet-irradiated compact amorphous solid water gradually decreased at temperatures above 60 K. Analyzing the temperature dependence of OH intensities with the Arrhenius equation, the decrease can be explained by the recombination of two OH radicals, which is rate-limited by thermal diffusion of OH. The activation energy for surface diffusion was experimentally determined for the first time to be 0.14 +/- 0.01 eV, which is larger than or equivalent to those assumed in theoretical models. This value implies that the diffusive reaction of OH radicals starts to be activated at approximately 36 K on interstellar ice.
Publisher	en American Astronomical Society
Date	Issued2022-11-14
Language	eng
Resource Type	journal article
Version Type	NA
Identifier	HDL http://hdl.handle.net/2115/87548
Relation	isIdenticalTo DOI https://doi.org/10.3847/2041-8213/ac9d30
Journal	PISSN 2041-8205 en The Astrophysical journal letters Volume Number940 Page StartL2
Oaidate	2023-07-26