COHERENCE PARAMETERS FOR ELECTRON-CAPTURE IN H(+)+HE COLLISIONS

The classical trajectory Monte Carlo method is used to calculate coherence parameters for electron capture to H(n = 2, 3 and 4) in 30 to 250 keV H+ + He collisions. The parameters evaluated are the x- and z-components of the dipole moment [D] and the z-component of the perihelion velocity of the captured electron (L x A). The calculated integral values are found to be in reasonable agreement with available experimental results. Components of the dipole moment and [L x A] were also evaluated as a function of projectile scattering angle. Here, rapid variations of the parameters are observed near the Thomas angle that indicate the transition from the hard, large angle collisions between the projectile and target nucleus to the soft, small angle scattering between the projectile and active electron.