Stokes-parameter measurements for spin-polarized electron-impact excitation of the 6s6p (J = 1) states in mercury

The intermediate-coupling nature of the two 6s6p (J = 1) states in mercury makes it possible to observe exchange effects in both excitation processes. The general assumption is that the excitation of the 1P1 state is affected by exchange only for energies very close to the excitation threshold, whereas exchange is strongly affecting the excitation of the 3P1 state with just a slowly decreasing influence towards higher impact energies. With a special focus on this, Stokes-parameters from coincidence as well as angle-integrated measurements for the corresponding 185 nm and 254 nm lines are presented alongside theoretical predictions.