تقرير
Model-potential calculations of positron binding, scattering, and annihilation for atoms and small molecules, using a Gaussian basis
| العنوان: | Model-potential calculations of positron binding, scattering, and annihilation for atoms and small molecules, using a Gaussian basis |
|---|---|
| المؤلفون: | Swann, A. R., Gribakin, G. F. |
| المصدر: | Phys. Rev. A 101, 022702 (2020) |
| سنة النشر: | 2019 |
| المجموعة: | Physics (Other) |
| مصطلحات موضوعية: | Physics - Atomic Physics |
| الوصف: | A model-potential method is employed to calculate binding, elastic scattering, and annihilation of positrons for a number of atoms and small nonpolar molecules, namely, Be, Mg, He, Ar, H$_2$, N$_2$, Cl$_2$, and CH$_4$. The model potential contains one free parameter for each type of atom within the target. Its values are chosen to reproduce existing ab initio positron-atom binding energies or scattering phase shifts. The calculations are performed using a Gaussian basis for the positron states, and we show how to obtain values of the scattering phase shifts and normalized annihilation rate $Z_{\rm eff}$ from discrete positive-energy pseudostates. Good agreement between the present results and existing calculations and experimental data, where available, is obtained, including the $Z_{\rm eff}$ value for CH$_4$, which is strongly enhanced by a low-lying virtual positron state. An exception is the room-temperature value of $Z_{\rm eff}$ for Cl$_2$, for which the present value is much smaller than the experimental value obtained over 50 years ago. Our calculations predict that among the molecular targets studied, only Cl$_2$ might support a bound state for the positron, with a binding energy of a few meV. Comment: 23 pages, 10 figures, accepted in Phys. Rev. A |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1103/PhysRevA.101.022702 |
| URL الوصول: | http://arxiv.org/abs/1912.03051 |
| رقم الأكسشن: | edsarx.1912.03051 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1103/PhysRevA.101.022702 |
|---|