The excited-projectile state density matrix is derived from the impact-parameter version of the Oppenheimer-Brinkman-Kramers approximation for a one electron-capture process from localized target states The result is used to determine the Stokes parameters of the emitted light General conditions for the production of atomic orientation are investigated and the connection to a recently published classical model is established Large values of atomic orientation and alignment are found for capture into a hydrogenic 2p state of the projectile A simple model for the beam-tilted-foil interaction yields a sinβ dependence of the circular polarization on the tilt angleβ Model calculations for beam-surface scattering show good agreement with experimental data for the relative Stokes parameters

Theory of optical polarization due to electron capture from localized target states by fast ions

A partial-wave analysis for orientation parameters in atomic collision processes has been formulated by using a coordinate system with its z axis perpendicular to the collision plane. The result is interpreted in terms of the intuitive model of grazing collisions. Details are illustrated for the electron impact induced Na(32S to 32P) transition.

https://iopscience.iop.org/article/10.1088/0022-3700/13/21/021/pdf

Orientation in atomic collisions: correspondence of classical model and partial-wave analysis

Elliptic polarization from grazing-incidence collisions of hydrogen ions on polycrystalleve and single-crystal surfaces

Using singly or doubly reflected 270keV-ions from a Cu-surface at grazing incidence nuclear polarizations in7Li ofPI=(6.8±0.6) % orPI= (11.5±1.0) % and in14N ofPI =(14.8±1.0) % orPI=(20.0±1.0) % respectively, have been achieved.

Nuclear polarized7Li and14N ions via ion beam surface interaction at grazing incidence

A quasi coincident method selective to impact parameters has been employed to determine four out of five possible density matrix elements of the Hel 33P excited term after He+(1s)+Ne(2p6)→HeI(33P)+Ne+(?) collision processes for the He+ energies from 10 to 355 keV

Observation of the HeI 33P polarization after medium energy He+ — Ne collisions with impact parameter selection

We have investigated the grazing-angle scattering of fast ions from solid surfaces. We establish that the circular polarization of light emitted from the scattered ions, and hence the ion orientation, varies strongly with the ion scattering angle. We show that the nearly elastic ion-surface collisions produce maximum allowed orientation of states with very small alignment.

J. Desesquelles

Papers

Spatial distribution of orientation of fast ions excited by surface-grazing collisions