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Title: Ortho-para conversion of hydrogen on films of rare-earth metals

Abstract

This study concerns the comparative study of the specific catalytic activity of rare-earth metals and shows how far a change in the electron structure of the metals can affect their catalytic properties. The ortho-para conversion at 77/sup 0/K has been used as the model reaction. Scandium and all the lanthanoids except europium and promethium were prepared in the form of vacuum-evaporated films. Other conditions were 0.5 torr; n/sub 0/ = 10/sup 15/ is the number of metal atoms on the surface; F/sub a/ = 1 is the proportion of paramagnetic metal atoms; and O = the degree of filling of the surface by the physically adsorbed hydrogen molecules. The results established that the rare earth metals as catalysts of a low temperature ortho-hydrogen conversion are divided into two groups which differ in the mechanism by which the reaction occurs. A comparison between the experimental results and the calculated results of the absolute rates of the paramagnetic conversion and also with the results of a study of isotopic exchange for these metals leads to the conclusion that for metals of the first group the conversion occurs by a chemical mechanism and for metals of the second group, by a vibrational magneticmore » mechanism. 3 figures, 1 table.« less

Authors:
;
Publication Date:
Research Org.:
Moscow Chemical-Engineering Inst., USSR
OSTI Identifier:
5689881
Resource Type:
Journal Article
Journal Name:
Dokl. Phys. Chem. (Engl. Transl.); (United States)
Additional Journal Information:
Journal Volume: 246:4-6; Other Information: Translated from Dokl. Akad. Nauk SSSR; 246: No. 6, 1395-1399(Jun 1979)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 08 HYDROGEN; HYDROGEN; SPIN ORIENTATION; RARE EARTHS; CATALYTIC EFFECTS; SCANDIUM; CATALYSTS; CHEMICAL REACTION KINETICS; EXPERIMENTAL DATA; FILMS; ISOLATED VALUES; LOW TEMPERATURE; MEDIUM VACUUM; PRESSURE DEPENDENCE; TEMPERATURE DEPENDENCE; CRYOGENIC FLUIDS; DATA; DATA FORMS; ELEMENTS; FLUIDS; INFORMATION; KINETICS; METALS; NONMETALS; NUMERICAL DATA; ORIENTATION; REACTION KINETICS; TRANSITION ELEMENTS; 400201* - Chemical & Physicochemical Properties; 080800 - Hydrogen- Properties & Composition

Citation Formats

Zhavoronkova, K N, and Peshkov, A V. Ortho-para conversion of hydrogen on films of rare-earth metals. United States: N. p., 1979. Web.
Zhavoronkova, K N, & Peshkov, A V. Ortho-para conversion of hydrogen on films of rare-earth metals. United States.
Zhavoronkova, K N, and Peshkov, A V. Sat . "Ortho-para conversion of hydrogen on films of rare-earth metals". United States.
@article{osti_5689881,
title = {Ortho-para conversion of hydrogen on films of rare-earth metals},
author = {Zhavoronkova, K N and Peshkov, A V},
abstractNote = {This study concerns the comparative study of the specific catalytic activity of rare-earth metals and shows how far a change in the electron structure of the metals can affect their catalytic properties. The ortho-para conversion at 77/sup 0/K has been used as the model reaction. Scandium and all the lanthanoids except europium and promethium were prepared in the form of vacuum-evaporated films. Other conditions were 0.5 torr; n/sub 0/ = 10/sup 15/ is the number of metal atoms on the surface; F/sub a/ = 1 is the proportion of paramagnetic metal atoms; and O = the degree of filling of the surface by the physically adsorbed hydrogen molecules. The results established that the rare earth metals as catalysts of a low temperature ortho-hydrogen conversion are divided into two groups which differ in the mechanism by which the reaction occurs. A comparison between the experimental results and the calculated results of the absolute rates of the paramagnetic conversion and also with the results of a study of isotopic exchange for these metals leads to the conclusion that for metals of the first group the conversion occurs by a chemical mechanism and for metals of the second group, by a vibrational magnetic mechanism. 3 figures, 1 table.},
doi = {},
url = {https://www.osti.gov/biblio/5689881}, journal = {Dokl. Phys. Chem. (Engl. Transl.); (United States)},
number = ,
volume = 246:4-6,
place = {United States},
year = {1979},
month = {12}
}