Positronium Quenching with Nitric Oxide Targets: A Theoretical Study of Spin Coupling

A single elastic collision between an \textit{ortho} positronium beam and a nitric oxide target is considered. The spin coupling between \textit{ortho} positronium and the doublet ground state of nitric oxide leading to the production of both \textit{para} and \textit{ortho} positronium is studied. Angular momentum coupling and density matrix techniques are used to calculate the probabilities of forming \textit{para }and \textit{ortho} positronium in terms of total-electron-spin-dependent scattering amplitudes. The results are used to estimate the fraction of the incoming \textit{ortho} positronium that has been converted to \textit{para} positronium due to the exchange of the unpaired electron of the nitric oxide target with the electron of the incoming \textit{ortho} positronium.