Positron scattering and annihilation on noble gas atoms

Abstract

Positron scattering and annihilation on noble gas atoms below the positronium formation threshold is studied ab initio using many-body theory methods. The many-body theory provides a near-complete understanding of the positron-noble-gas-atom system at these energies and yields accurate numerical results. It accounts for positron-atom and electron-positron correlations, e.g., polarization of the atom by the incident positron and the non-perturbative process of virtual positronium formation. These correlations have a large effect on the scattering dynamics and result in a strong enhancement of the annihilation rates compared to the independent-particle mean-field description. Computed elastic scattering cross sections are found to be in good agreement with recent experimental results and Kohn variational and convergent close-coupling calculations. The calculated values of the annihilation rate parameter $Z_{\mathrm{eff}}$ (effective number of electrons participating in annihilation) rise steeply along the sequence of noble gas atoms due to the increasing strength of the correlation effects, and agree well with experimental data.

arXiv comment24 pages, 17 figures

References in corpus (10)

• Positron-molecule interactions: resonant attachment, annihilation, and bound states
• Mechanisms of positron annihilation on molecules
• Many-body theory of positron-atom interactions
• Many-body theory of gamma spectra from positron-atom annihilation
• Atoms which can bind positrons
• Positron-atom scattering using pseudo-state energy shifts
• Positron scattering and annihilation in hydrogen-like ions
• Positronium formation from valence and inner shells in noble gas atoms
• Relativistic coupled-cluster single-double calculations of positron-atom bound states
• Effect of positron-atom interactions on the annihilation gamma spectra of molecules

Cited by in corpus (26)

• Recent progress in the description of positron scattering from atoms using the Convergent Close-Coupling Theory
• Many-body theory of positron binding in polyatomic molecules
• $\gamma$-ray spectra and enhancement factors for positron annihilation spectra with core-electrons
• Positron Binding and Annihilation in Alkane Molecules
• Calculations of positron binding and annihilation in polyatomic molecules
• Model-potential calculations of positron binding, scattering, and annihilation for atoms and small molecules, using a Gaussian basis
• Many-body theory for positronium-atom interactions
• Effect of chlorination on positron binding to hydrocarbons: experiment and theory
• Mode coupling and multiquantum vibrational excitations in Feshbach-resonant positron annihilation in molecules
• Many-Body Theory Calculations of Positron Scattering and Annihilation in H${}_2$, N${}_2$ and CH${}_4$
• Accurate theoretical prediction on positron lifetime of bulk materials
• Calculations of positronium-atom scattering using a spherical cavity
• Positron cooling and annihilation in noble gases
• Effective radius of ground- and excited-state positronium in collisions with hard walls
• Many-body theory calculations of positronic-bonded molecular dianions
• Probing positron cooling in noble gases via annihilation $\gamma$ spectra
• Time-Dependent Multi-Component Density Functional Theory for Coupled Electron-Positron Dynamics
• Many-body theory for positronium scattering and pickoff annihilation in noble-gas atoms
• Positron elastic scattering by a semifilled-shell atom
• Comment on "Gamma-ray spectra from low-energy positron annihilation processes in molecules"
• Complex scaling calculation of phase shifts for positron collisions with positive ions
• Ab initio QED treatment of the two-photon annihilation of positrons with bound electrons
• Two-photon Annihilation of Positrons with K-shell Electrons of H-like ions
• Ground-state energy of quasi-free positrons in non-polar fluids
• Many-body theory predictions of positron binding energies in five-membered heterocycles involving N, O, S and NH substituents
• Coupled cluster theory for positron binding in anions and polyatomic molecules