Algorithm for Shifting Positron Annihilation Spectra

g-ray spectra from positron annihilation on atoms and molecules

Positron annihilation on a wide variety of atoms and molecules is studied. Room-temperature positrons confined in a Penning trap are allowed to interact with molecules in the form of low-pressure gases so that the interaction is restricted to binary encounters between a positron and a molecule. Data are presented for the g-ray spectra resulting from positrons annihilating in such interactions. ...

Many - body theory of gamma spectra from positron - atom annihilation

A many-body theory approach to the calculation of gamma spectra of positron annihilation on many-electron atoms is developed. We evaluate the first-order correlation correction to the annihilation vertex and perform numerical calculations for the noble gas atoms. Extrapolation with respect to the maximal orbital momentum of the intermediate electron and positron states is used to achieve conver...

a-axis-projected electron-positron-momentum density and positron-annihilation spectra in YBa2Cu3O7-x.

Positron Annihilation Spectroscopy

Positron annihilation spectroscopy is nowadays well recognised as a powerful tool of microstructure investigations of condensed matter. An overview of the method aimed for users from other fields is given and supplemented with several examples of applications.

γ-Ray spectra and enhancement factors for positron annihilation with core electrons.

Many-body theory is developed to calculate the γ spectra for positron annihilation in noble-gas atoms. Inclusion of electron-positron correlation effects and core annihilation gives spectra in excellent agreement with experiment [K. Iwata et al., Phys. Rev. Lett. 79, 39 (1997)]. The calculated correlation enhancement factors γ_{nl} for individual electron orbitals nl are found to scale with the...