Numerical Solution of a Two-Particle Model of Positronium Confined in Small Cavities

• Authors: G. Tanzi Marlotti , F. Castelli , G. Consolati
• Languages of publication: EN

Abstracts

EN

The positronium atom (Ps) is widely used as a probe to characterize nanoporous and mesoporous materials. Existing theoretical models for describing Ps annihilation rates by pick-off processes generally treat Ps as a point particle confined in a potential well. Hence these models do not justify any change in the internal structure of Ps, which is experimentally accessible by means of the contact density parameter. Recently we formulated a two-particle model in which only the electron is confined in the cavity, while the positron is moving freely and feels the medium via a positive work function. We present here a numerical treatment of the problem of calculating contact densities and pick-off annihilation rates, by using a variational method. Results are in agreement with experimental data for a large class of materials, and suggest a way to connect these data with pore sizes and positron work functions.

Keywords

EN

36.10.Dr; 34.80.Lx; 78.70.Bj

Discipline

• 34.80.Lx: Recombination, attachment, and positronium formation
• 78.70.Bj: Positron annihilation(for positron states, see 71.60.+z in electronic structure of bulk materials; for positronium chemistry, see 82.30.Gg in physical chemistry and chemical physics)
• 36.10.Dr: Positronium(see also 82.30.Gg Positronium chemistry)

• Journal: Acta Physica Polonica A
• Year: 2017
• Volume: 132
• Issue: 5
• Pages: 1575-1578

Dates

published

2017-11

Contributors

author

G. Tanzi Marlotti

• Department of Physics, Università degli Studi di Milano, via Celoria 16 I-20133 Milano, Italy

author

F. Castelli

• Department of Physics, Università degli Studi di Milano, via Celoria 16 I-20133 Milano, Italy
• INFN, sezione di Milano, via Celoria 16 I-20133 Milano, Italy

author

G. Consolati

• Department of Aerospace Science and Technology, Politecnico di Milano, via LaMasa 34, I-20156 Milano, Italy

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Identifiers

DOI

10.12693/APhysPolA.132.1575