Absolute differential (12 • -130 • ) cross sections for low energy (1-10 eV) electron scattering from argon have been measured on two separate and different spectrometers using the relative flow technique. The data have also been analysed using phaseshift techniques. Comparisons are made between the present cross sections and phaseshifts and similar data from previous experiments and theory. The results are particularly encouraging, with recent experiments and scattering theories being in good general agreement.

Differential cross section measurements for the elastic scattering of electrons from CH 3 Cl at energies from 0.5 to 9.5 eV are reported for scattering angles of 30°and 100°. The angular scattering dependence is determined at selected energies over this range. At energies below 1.0 eV, the cross sections are in excellent agreement with calculations using the Born dipole approximation. At large angles and higher energies, the scattering is dominated by a 2 A 1 temporary negative ion state near 3.5 eV. Energy loss data at 3.5, 5.0, and 8.5 eV are reported and the relative contributions of various vibrational modes determined. Differential cross sections for vibrational excitation of the 3 ͑a 1 ͒ C-Cl and 4 (e) CH stretching modes have been measured. The latter reveals a broad shape resonance of 2 E symmetry peaking near 5.5 eV. Angular distributions for excitation of these same modes are also reported. Using fittings to the vibrational excitation functions, the resonance parameters have been extracted and used in a mixed semiempirical ab initio calculation to compute the relative strengths of the vibrational energy loss peaks. These compare favorably with the results of the experiment. Elastic cross sections integrated over angle are reported for low energies. They are substantially larger than the results from recent measurements of the total cross section.

No abstract

The T1-Ba-Ca-Cu-0 superconducting films were synthesized by sputtering either from a single target or from two oxide targets in a symmetric configuration. Films with zero resistance T, of up to 122 I< were obtained after various post annealing treatment at 870 -950°C under oxygen atmosphere. We have studied morphology, structure, magnetic and superconducting properties of these films. Films prepared by two different sputtering techniques have similar results which depend mostly on the film compositions and their annealing conditions. We found that the induced magnetic flux in the film decrcases rapidly with increasing temperature, indicating the weak flux pinning.