Positronium Molecule Formation on Al (111)a

S.H.M. Deng; D.B. Cassidy; A.P. Mills

doi:10.4028/www.scientific.net/MSF.607.22

Paper Titles

Preface

Positronium Chemistry in Polymeric Membrane Systems
p.1

Resonant Positron Annihilation on Molecules
p.9

Prospects for Laser Spectroscopy of Ps₂
p.17

Positronium Molecule Formation on Al (111)^a
p.22

Dipositronium and other Two-Positronium Compounds
p.25

Ortho-Positronium Reemission Yield and Energy in Surfactant-Templated Mesoporous Silica Films
p.30

Collisions Involving Positrons and Positronium
p.34

Positronium Thermalization Process in Nanoporous Materials and its Influence on the Shape of PALS Spectrum
p.39

HomeMaterials Science ForumMaterials Science Forum Vol. 607Positronium Molecule Formation on Al (111)a

Positronium Molecule Formation on Al (111)^a

Abstract:

A single crystal Al (111) sample cleaned by repeated cycles of ion bombardment and annealing was irradiated by a subnanosecond high density positron beam [1] and the resulting positronium lifetime spectra were measured using single shot positron annihilation lifetime spectroscopy (SSPALS) [2]. We observed the amount of positronium emitted dependence on the incident positron beam density, which indicates the formation of positronium molecules (Ps2) at the Al (111) surface [3]. The Ps2 formation probability appears to be extremely sensitive to surface contamination and further experiments under improved vacuum conditions are planned to clarify this effect.