Abstract
We investigate molecular scale mechanisms for radiation-induced release of hydrogen from precursor sites using density functional theory applied to a fully periodic model of SiO2. We focus on proton release from H-decorated oxygen vacancies in the bulk oxide. After hole-capture at the vacancy, a proton can hop to an energetically favorable bound state at a neighboring oxygen atom. In α-quartz, this release mechanism has an activation energy of about 1.2 eV. In amorphous silica, this hop has a range of low barriers, from 0.1 to 0.5 eV. Furthermore, another proton release mechanism involves cracking of H2 molecules by a reaction with an isolated, positively charged Si-dangling bond.
Original language | English (US) |
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Pages (from-to) | 274-278 |
Number of pages | 5 |
Journal | Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms |
Volume | 250 |
Issue number | 1-2 SPEC. ISS. |
DOIs | |
State | Published - Sep 2006 |
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
- Instrumentation