Positron annihilation and binding in aromatic and other ring molecules
- Resource Type
- Working Paper
- Authors
- Arthur-Baidoo, E.; Danielson, J. R.; Surko, C. M.; Cassidy, J. P.; Gregg, S. K.; Hofierka, J.; Cunningham, B.; Patterson, C. H.; Green, D. G.
- Source
- Phys. Rev. A 109, 062801 (2024)
- Subject
- Physics - Chemical Physics
Physics - Atomic and Molecular Clusters
Physics - Atomic Physics
Physics - Computational Physics
Quantum Physics
- Language
Annihilation spectra are presented for aromatic and heterocyclic ring molecules resolved as a function of incident positron energy using a trap-based positron beam. Comparisons with the vibrational mode spectra yield positron-molecule binding energies. Good to excellent agreement is found between the measured binding energies and the predictions of an \textit{ab initio} many-body theory that takes proper account of electron-positron correlations including virtual-positronium formation. The calculations elucidate the competition between permanent dipole moments and $\pi$ bonds in determining the spatial distribution of the bound-state positron density. The implications of these results and the role of multimode features in annihilation in these molecules, including Fermi resonances, are discussed.