Neutralization of solvated protons and formation of noble-gas hydride molecules: Matrix-isolation indications of tunneling mechanisms?
- Laboratory of Physical Chemistry, P.O. Box 55, University of Helsinki, Helsinki FIN-00014 (Finland)
The (NgHNg){sup +} cations (Ng=Ar and Kr) produced via the photolysis of HF/Ar, HF/Kr, and HBr/Kr solid mixtures are studied, with emphasis on their decay mechanisms. The present experiments provide a large variety of parameters connected to this decay phenomenon, which allows us to reconsider various models for the decay of the (NgHNg){sup +} cations in noble-gas matrices. As a result, we propose that this phenomenon could be explained by the neutralization of the solvated protons by electrons. The mechanism of this neutralization reaction probably involves tunneling of an electron from an electronegative fragment or another trap to the (NgHNg){sup +} cation. The proposed electron-tunneling mechanism should be considered as a possible alternative to the literature models based on tunneling-assisted or radiation-induced diffusion of protons in noble-gas solids. As a novel experimental observation of this work, the efficient formation of HArF molecules occurs at 8 K in a photolyzed HF/Ar matrix. It is probable that the low-temperature formation of HArF involves local tunneling of the H atom to the Ar-F center, which in turn supports the locality of HF photolysis in solid Ar. In this model, the decay of (ArHAr){sup +} ions and the formation of HArF molecules observed at low temperatures are generally unconnected processes; however, the decaying (ArHAr){sup +} ions may contribute to some extent to the formation of HArF molecules.
- OSTI ID:
- 20723022
- Journal Information:
- Journal of Chemical Physics, Vol. 123, Issue 6; Other Information: DOI: 10.1063/1.1953467; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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