Cargando…

Long-Time Non-Debye Kinetics of Molecular Desorption from Substrates with Frozen Disorder

The experiments on the kinetics of molecular desorption from structurally disordered adsorbents clearly demonstrate its non-Debye behavior at “long” times. In due time, when analyzing the desorption of hydrogen molecules from crystalline adsorbents, attempts were made to associate this behavior with...

Descripción completa

Detalles Bibliográficos
Autores principales: Bondarev, Victor N., Kutarov, Volodymyr V., Schieferstein, Eva, Zavalniuk, Vladimir V.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7464774/
https://www.ncbi.nlm.nih.gov/pubmed/32796720
http://dx.doi.org/10.3390/molecules25163662
_version_ 1783577440733364224
author Bondarev, Victor N.
Kutarov, Volodymyr V.
Schieferstein, Eva
Zavalniuk, Vladimir V.
author_facet Bondarev, Victor N.
Kutarov, Volodymyr V.
Schieferstein, Eva
Zavalniuk, Vladimir V.
author_sort Bondarev, Victor N.
collection PubMed
description The experiments on the kinetics of molecular desorption from structurally disordered adsorbents clearly demonstrate its non-Debye behavior at “long” times. In due time, when analyzing the desorption of hydrogen molecules from crystalline adsorbents, attempts were made to associate this behavior with the manifestation of second-order effects, when the rate of desorption is limited by the rate of surface diffusion of hydrogen atoms with their subsequent association into molecules. However, the estimates made in the present work show that the dominance of second-order effects should be expected in the region of times significantly exceeding those where the kinetics of H(2) desorption have long acquired a non-Debye character. To explain the observed regularities, an approach has been developed according to which frozen fluctuations in the activation energy of desorption play a crucial role in the non-Debye kinetics of the process. The obtained closed expression for the desorption rate has a transparent physical meaning and allows us to give a quantitative interpretation of a number of experiments on the desorption kinetics of molecules not only from crystalline (containing frozen defects) but also from amorphous adsorbents. The ways of further development of the proposed theory and its experimental verification are outlined.
format Online
Article
Text
id pubmed-7464774
institution National Center for Biotechnology Information
language English
publishDate 2020
publisher MDPI
record_format MEDLINE/PubMed
spelling pubmed-74647742020-09-04 Long-Time Non-Debye Kinetics of Molecular Desorption from Substrates with Frozen Disorder Bondarev, Victor N. Kutarov, Volodymyr V. Schieferstein, Eva Zavalniuk, Vladimir V. Molecules Article The experiments on the kinetics of molecular desorption from structurally disordered adsorbents clearly demonstrate its non-Debye behavior at “long” times. In due time, when analyzing the desorption of hydrogen molecules from crystalline adsorbents, attempts were made to associate this behavior with the manifestation of second-order effects, when the rate of desorption is limited by the rate of surface diffusion of hydrogen atoms with their subsequent association into molecules. However, the estimates made in the present work show that the dominance of second-order effects should be expected in the region of times significantly exceeding those where the kinetics of H(2) desorption have long acquired a non-Debye character. To explain the observed regularities, an approach has been developed according to which frozen fluctuations in the activation energy of desorption play a crucial role in the non-Debye kinetics of the process. The obtained closed expression for the desorption rate has a transparent physical meaning and allows us to give a quantitative interpretation of a number of experiments on the desorption kinetics of molecules not only from crystalline (containing frozen defects) but also from amorphous adsorbents. The ways of further development of the proposed theory and its experimental verification are outlined. MDPI 2020-08-11 /pmc/articles/PMC7464774/ /pubmed/32796720 http://dx.doi.org/10.3390/molecules25163662 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Bondarev, Victor N.
Kutarov, Volodymyr V.
Schieferstein, Eva
Zavalniuk, Vladimir V.
Long-Time Non-Debye Kinetics of Molecular Desorption from Substrates with Frozen Disorder
title Long-Time Non-Debye Kinetics of Molecular Desorption from Substrates with Frozen Disorder
title_full Long-Time Non-Debye Kinetics of Molecular Desorption from Substrates with Frozen Disorder
title_fullStr Long-Time Non-Debye Kinetics of Molecular Desorption from Substrates with Frozen Disorder
title_full_unstemmed Long-Time Non-Debye Kinetics of Molecular Desorption from Substrates with Frozen Disorder
title_short Long-Time Non-Debye Kinetics of Molecular Desorption from Substrates with Frozen Disorder
title_sort long-time non-debye kinetics of molecular desorption from substrates with frozen disorder
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7464774/
https://www.ncbi.nlm.nih.gov/pubmed/32796720
http://dx.doi.org/10.3390/molecules25163662
work_keys_str_mv AT bondarevvictorn longtimenondebyekineticsofmoleculardesorptionfromsubstrateswithfrozendisorder
AT kutarovvolodymyrv longtimenondebyekineticsofmoleculardesorptionfromsubstrateswithfrozendisorder
AT schiefersteineva longtimenondebyekineticsofmoleculardesorptionfromsubstrateswithfrozendisorder
AT zavalniukvladimirv longtimenondebyekineticsofmoleculardesorptionfromsubstrateswithfrozendisorder