Electron exchanges in nuclear spin conversion of hydrogen physisorbed on diamagnetic insulators

Ernest Ilisca () and Filippo Ghiglieno

The European Physical Journal B: Condensed Matter and Complex Systems, 2014, vol. 87, issue 10, 1-29

Abstract: Models are provided and discussed to interpret new experiments on the ortho-para conversion of hydrogen “physisorbed” on dielectric and diamagnetic surfaces. Electro-static and dynamical molecule-surface interactions complemented by hyperfine contacts are shown to be generally more effective than the magnetic ones. Coulomb repulsion induces exchanges of molecular and surface electrons and excites triplet spin states which are effective in the angular momenta transfers to the catalyst. The conversion time is obtained as the square of a ratio of two energies: the exchange and excitation ones. The main channel is found composed of triplet excitations of the order of the eV, induced by molecule-surface exchanges of about a hundred of meV. It explains the zinc and oxygen rates of about one minute observed on the MOF samples as well as the about ten times slower ones on the ASW. The same mechanism is also shown to occur in the transient regime, but faster. Finally it explains also the conversion of a few hours observed for interstitial hydrogen in silicium by transitions to the conduction band induced by about 10 meV electron exchanges. The molecule-surface orbital geometries of the MOF and ASW configurations are displayed and the quantum path when unfolded exhibits the successive broken symmetries. Copyright EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2014

Keywords: Solid State and Materials (search for similar items in EconPapers)
Date: 2014
References: View complete reference list from CitEc
Citations:

Downloads: (external link)
http://hdl.handle.net/10.1140/epjb/e2014-50282-2 (text/html)
Access to full text is restricted to subscribers.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:spr:eurphb:v:87:y:2014:i:10:p:1-29:10.1140/epjb/e2014-50282-2

Ordering information: This journal article can be ordered from
http://www.springer.com/economics/journal/10051

DOI: 10.1140/epjb/e2014-50282-2

Access Statistics for this article

The European Physical Journal B: Condensed Matter and Complex Systems is currently edited by P. Hänggi and Angel Rubio

More articles in The European Physical Journal B: Condensed Matter and Complex Systems from Springer, EDP Sciences
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().