{"paper":{"title":"Many-body theory and Gaussian-basis implementation of positron annihilation $\\gamma$-ray spectra on polyatomic molecules","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["physics.atm-clus","physics.chem-ph","physics.comp-ph","quant-ph"],"primary_cat":"physics.atom-ph","authors_text":"A. R. Swann, B. Cunningham, D. G. Green, J. Hofierka, J. P. Cassidy, S. K. Gregg","submitted_at":"2025-02-17T22:58:31Z","abstract_excerpt":"Doppler-broadened $\\gamma$-ray spectra for positron annihilation on molecules are calculated using many-body theory. By employing Gaussian bases for the electron and positron wavefunctions, a computable expression that involves a four-centre integral over the two-annihilation-photon momenta is derived for the $\\gamma$ spectra in the independent particle model approximation to the annihilation vertex, and implemented in the open-source {\\tt EXCITON+} code. The influence of electron-positron correlations on the $\\gamma$ spectra is examined through \\textit{ab initio} treatment of the positron wav"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2502.12364","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2502.12364/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}