Abstract
Positron annihilation rates in many polyatomic molecular gases are anomalously high. Qualitatively, this can be explained by positron capture in vibrational Feshbach resonances, which can occur for molecules with positive positron affinities [Gribakin, Phys. Rev. A 61 (2000) 022720]. To verify this idea quantitatively, we examine the densities of vibrational excitation spectra of alkanes. To understand the energy dependence of the annihilation rates for alkanes, we propose that positron capture is mediated by vibrational doorway states, in which positron binding is accompanied by the excitation of fundamentals.
Original language | English |
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Pages (from-to) | 30-35 |
Number of pages | 6 |
Journal | Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms |
Volume | 221 |
Early online date | 13 Apr 2004 |
DOIs | |
Publication status | Published - Jul 2004 |
Keywords
- vibrational doorway states
- positron annihilation
- large molecules
ASJC Scopus subject areas
- Surfaces, Coatings and Films
- Instrumentation
- Surfaces and Interfaces