Feshbach projection operator approach to positron annihilation
نویسندگان
چکیده
منابع مشابه
Feshbach-resonance-mediated positron annihilation in small molecules
Large positron annihilation cross sections have been observed for a variety of molecules at various energies below the threshold for positronium formation. These large values are due to vibrational Feshbach resonances VFRs , in which the positron attaches to the molecule while exciting a vibration. This leads to rates of annihilation far greater than those expected for a simple collision. The d...
متن کاملFeshbach-resonance-mediated annihilation in positron interactions with large molecules
Measurements of positron-on-molecule annihilation have established that positrons attach to a variety of molecules via vibrational Feshbach resonances VFRs . These resonances, in turn, result in greatly enhanced positron annihilation rates beyond those expected in simple collisions. A recent paper J. A. Young and C. M. Surko, Phys. Rev. Lett. 99, 133201 2007 described experimental studies and a...
متن کاملRole of binding energy in Feshbach-resonant positron-molecule annihilation.
Measurements of positron-on-molecule annihilation have established that positrons bind to a variety of molecules via vibrational Feshbach resonances. Data for deeply bound states in benzene and 1-chlorohexane and for positronically excited (i.e., second) bound states in alkanes are used to establish the dependence of annihilation rates on the binding energy and incident positron energy. With th...
متن کاملEnhancement of positron annihilation on molecules due to vibrational Feshbach resonances
The zero-range potential model is used to investigate positron collisions and annihilation with molecules. The Kr2 dimer is considered as an example. It is shown that (i) although positrons do not bind to individual Kr atoms, they do form bound states with Kr2. (ii) A sequence of vibrationally excited states of the positron–molecule complex extends into the positron continuum, where it manifest...
متن کاملProjection Operator Approach to Constrained Systems
Recently, within the context of the phase space coherent state path integral quantisation of constrained systems, John Klauder introduced a reproducing kernel for gauge invariant physical states, which involves a projection operator onto the reduced Hilbert space of physical states, avoids any gauge fixing conditions, and leads to a specific measure for the integration over Lagrange multipliers...
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ژورنال
عنوان ژورنال: Physical Review A
سال: 2009
ISSN: 1050-2947,1094-1622
DOI: 10.1103/physreva.80.052710