LASER-ASSISTED COLLISIONS OF ELECTRONS WITH METAL VAPORS

Three separate experiments are described which use laser radiation to probe the details of electron scattering processes from metal vapour t argets. Results from superelastic scattering experiments from calcium are presented. The experiments were carried out at incident energies o f 25 . 7 and 45 eV referred to the ground state. Scattering amplitudes derived from these experiments demonstrate that current theories are inadequate. The coherence of the excitation process has been studied b y measuring the total polarisation. It is shown that the excitation pr ocess is coherent over the whole kinematic range. Preliminary results from a study of superelastic electron scattering from lithium are disc ussed where it is shown that a quantum electrodynamical model can be u sed to describe the optical pumping process in Li-6 and Li-7. In addit ion the first superelastic electron spectrum is presented for experime nts on lithium. A stepwise excitation technique is described with whic h cross sections for the electron impact excitation of the 3d(9)-4s(2) D-2 state in copper can be measured. The experiments are complicated by the presence of D states in the incident copper beam. The origin of these D states is described as is a modification of the technique whi ch leads to their removal.