The complete set of generalized STU parameters are presented for el-tic and inelastic scattering of polarized electrons from unpolarized thallium atoms. Some of these parameters can only be measured in 'triple scattering experiments', since the change of the initial polarization vector has to be determined. Numerical results from a semi-relativistic Breit-Pauli R-matrix calculation are compared with recent experimental data obtained by the Miinster group for the asymmetry function SA. The agreement is very satisfactory, and the overall structure of the results indicates the importance of the line-structure effect-even for very heavy target systems.

We consider the scattering of transversely polarized elecbnns by spatially oriented and rotating oxygen molecules, and present results fw polarization fractions and differential cmss sections. We show that the polarization fiaction can deviate significantly from uniry.unlike the randomly oriented case, for some molecular orientations and rotational transitions. These deviations occur when the differential cross sections are small and their conuibution to the randomly oriented case is small.

Numerical results for the complete set of generalized STU-parameters are presented for elastic scattering of polarized electrons from unpolarized thallium and lead atoms. Some of these parameters can only be measured in "triple scattering experiments", since the change of the initial polarization vector has to be determined. The agreement between the predictions of semirelativistic Breit-Pauli R-matrix calculations and recent experimental data of the Miinster group for the Sherman function S is excellent in the case of thallium while further improvements of the theoretical model are necessary for the lead target.

We consider the rotationally resolved excitation of homonuclear Hunds case (b) molecules by unpolarized electrons. The general theory is developed and the relevant selection rules are given. Using recently obtained R-matrix elements for the a1 Delta g and b1 Sigma g+ excitation of O2, we have calculated orientation and alignment parameters for various scattering energies and angles. General features of these parameters, which might be valid for excitation of other molecules as well, are pointed out. In particular it is shown that no rotation of the electronic charge cloud around the molecular axis can be produced during the collision.

Abstract. Rotationally resolved excitation of the a*Ag and blZgStates of 0 2 is considered. Results for the relevant state multipoles are given. The anisotropy produced by electron impact is visualised by figures of the angular distribution of the molecular axes in the excited states.