Proton stopping in dense molecular hydrogen: A molecular-confinement model
| Autor: | Salvador A. Cruz, Eugene G Gamaly, J. Soullard |
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| Rok vydání: | 1999 |
| Předmět: | |
| Zdroj: | Physical Review A. 60:2207-2214 |
| ISSN: | 1094-1622 1050-2947 |
| DOI: | 10.1103/physreva.60.2207 |
| Popis: | A molecular-confinement model is proposed for the calculation of density effects on the electronic stopping cross section ${(S}_{e})$ in a condensed medium. In this model, the collective intermolecular interactions in the medium are represented by a mean field in which a particular molecule is embedded including the spatial constrictions imposed by the surrounding molecules. A molecule is thus viewed as a caged-in system within a spherical boundary with finite potential barrier height ${V}_{B}.$ Changes in the molecular electronic properties and molecular conformation as a function of medium density are self-consistently treated. As a first example of a general treatment for more complicated target structures, the model is explicitly applied to the case of proton stopping in dense molecular hydrogen. The lowest barrier height ${(V}_{B}=0)$ was selected for the stopping calculations since it provides a more realistic pressure-density relation at $T=0\mathrm{K}$ than higher barrier values. Our results for dense molecular hydrogen predict a very small to moderate reduction in ${S}_{e}$ relative to the gas phase in going from atmospheric pressure (0.036 ${\mathrm{m}\mathrm{o}\mathrm{l}/\mathrm{c}\mathrm{m}}^{3}$, $\ensuremath{\Delta}{S}_{e}\ensuremath{\approx}0.5%$) up to 136 GPa (0.380 ${\mathrm{m}\mathrm{o}\mathrm{l}/\mathrm{c}\mathrm{m}}^{3}$, $\ensuremath{\Delta}{S}_{e}\ensuremath{\approx}24%$) for either the liquid or solid phase as determined by the phase diagram for this medium. |
| Databáze: | OpenAIRE |
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