Work

Impact of vibrational Feshbach resonances on positron thermalization: a Monte Carlo simulation study

Year: 2025

Type: article

Abstract: In this article, we investigate the impact of vibrational Feshbach resonances (VFRs) on positron thermalization and annihilation in molecular gases using a Monte Carlo collision simulation approach. The Kr2 dimer, a benchmark system with a well-characterized VFR, is employed to analyze how resonances affect the positron speed distribution (PSD) and the thermally averaged annihilation parameter Z ¯ eff . Cross sections for elastic, vibrational, rotational, and annihilation processes are included in the simulation, calculated using the zero-range potential approximation. By comparing the resonant model with a non-resonant counterpart, we demonstrate that VFRs can strongly distort the PSD, leading to significant deviations from Maxwell–Boltzmann statistics and substantial overestimation of Z ¯ eff if equilibrium is assumed. Despite having little effect on the thermalization rate, resonances greatly influence the positron lifetime and annihilation probability. These findings highlight the necessity of accounting for non-equilibrium effects in positron interaction models, particularly for molecular systems exhibiting sharp vibrational resonances.

Source: Journal of Physics B Atomic Molecular and Optical Physics

DOI: 10.1088/1361-6455/ae0a9c

Authors: Eliton Popovicz Seidel, Jan Franz

Institution: Gdańsk University of Technology

Language: English

Topic: Atomic and Molecular Physics

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,325

Funder: Politechnika Gdańska