Journal of Physics B: Atomic and Molecular Physics, 1976
The cross section ratio for the symmetric (e,2e) reaction on helium leading to the n=2 and ground... more The cross section ratio for the symmetric (e,2e) reaction on helium leading to the n=2 and ground states of the helium ion has been calculated as a function of the ion recoil momentum q, using a correlated helium wavefunction, and compared with the results of a 1200 eV non-coplanar experiment and some previous results at 800 eV. The calculation agrees well with the measured (e,2e) cross section ratios and at high q with ratios measured in photoelectron spectroscopy experiments.
Journal of Physics B: Atomic, Molecular and Optical Physics, 1989
Relative differential cross sections for the asymmetric coplanar (e, 2e) reaction have been measu... more Relative differential cross sections for the asymmetric coplanar (e, 2e) reaction have been measured in three energy-sharing regions, for two of which the ionisation peak is about 1 au off the Bethe ridge. Momentum transfer is intermediate between large (binary) and small (dipole) values, where the distorted-wave impulse and second Born approximations respectively give a good account of the experimental data. In addition to these approximations the distorted-wave Born approximation is calculated. It is somewhat superior to the distorted-wave impulse approximation and very much better then the second Born approximation.
Abstract Measurements are reported on the spectroscopy of methane using the symmetric (e,2e) tech... more Abstract Measurements are reported on the spectroscopy of methane using the symmetric (e,2e) technique at energies of 600 eV and 1200 eV. The angular correlations of the states with separation energies of 14.2 and 23.1 eV have been measured and compared with the orbital wavefunctions of Snyder and Basch and with some earlier data at 400eV. The angular correlation of the configuration interaction state at 31 eV shows that this state definetely results from the removal of an electron in the 2a 1 orbital. Other structure at high separation energy is also identified with this orbital. Relative strengths of the It 2 and 2a 1 states are compared and found to be in agreement with the theory at 1200eV.
Abstract The relative intensities for exciting the 1sσg, 2pσu, 2pπu, and 2sσg states of H2 are me... more Abstract The relative intensities for exciting the 1sσg, 2pσu, 2pπu, and 2sσg states of H2 are measured in a 1200 eV noncoplanar symmetric (e,2e) experiment on H2. Momentum distributions are obtained at separation energies corresponding to the various transitions. The ratio of transition probability to the excited states relative to the ground state is strongly dependent on the ion recoil momentum q, having a minimum value of approximately 2% at small q. The excited state cross sections are sensitive to electron correlation effects and the data are compared with calculated cross sections using a configuration interaction wavefunction for H2.
Journal of Physics B: Atomic and Molecular Physics, 1976
The cross section ratio for the symmetric (e,2e) reaction on helium leading to the n=2 and ground... more The cross section ratio for the symmetric (e,2e) reaction on helium leading to the n=2 and ground states of the helium ion has been calculated as a function of the ion recoil momentum q, using a correlated helium wavefunction, and compared with the results of a 1200 eV non-coplanar experiment and some previous results at 800 eV. The calculation agrees well with the measured (e,2e) cross section ratios and at high q with ratios measured in photoelectron spectroscopy experiments.
Journal of Physics B: Atomic, Molecular and Optical Physics, 1989
Relative differential cross sections for the asymmetric coplanar (e, 2e) reaction have been measu... more Relative differential cross sections for the asymmetric coplanar (e, 2e) reaction have been measured in three energy-sharing regions, for two of which the ionisation peak is about 1 au off the Bethe ridge. Momentum transfer is intermediate between large (binary) and small (dipole) values, where the distorted-wave impulse and second Born approximations respectively give a good account of the experimental data. In addition to these approximations the distorted-wave Born approximation is calculated. It is somewhat superior to the distorted-wave impulse approximation and very much better then the second Born approximation.
Abstract Measurements are reported on the spectroscopy of methane using the symmetric (e,2e) tech... more Abstract Measurements are reported on the spectroscopy of methane using the symmetric (e,2e) technique at energies of 600 eV and 1200 eV. The angular correlations of the states with separation energies of 14.2 and 23.1 eV have been measured and compared with the orbital wavefunctions of Snyder and Basch and with some earlier data at 400eV. The angular correlation of the configuration interaction state at 31 eV shows that this state definetely results from the removal of an electron in the 2a 1 orbital. Other structure at high separation energy is also identified with this orbital. Relative strengths of the It 2 and 2a 1 states are compared and found to be in agreement with the theory at 1200eV.
Abstract The relative intensities for exciting the 1sσg, 2pσu, 2pπu, and 2sσg states of H2 are me... more Abstract The relative intensities for exciting the 1sσg, 2pσu, 2pπu, and 2sσg states of H2 are measured in a 1200 eV noncoplanar symmetric (e,2e) experiment on H2. Momentum distributions are obtained at separation energies corresponding to the various transitions. The ratio of transition probability to the excited states relative to the ground state is strongly dependent on the ion recoil momentum q, having a minimum value of approximately 2% at small q. The excited state cross sections are sensitive to electron correlation effects and the data are compared with calculated cross sections using a configuration interaction wavefunction for H2.
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