J. Dellwo

Angular distribution of electrons photodetached from the excited negative ion of carbon

A crossed beam technique has been used to investigate the angular distribution of electrons photodetached from the weakly-bound excited (2p3)2D state of the C- ion via the (2p2) 3P epsilon s,d channels. At a photon energy of 2.076 eV the asymmetry parameter was measured to be 0.38+or-0.05. No theoretical predictions are currently available.

Angular distributions of electrons photodetached from the B− ion

A crossed-beams apparatus has been used to measure, for the first time, the angular distributions of electrons photodetached from B− ions. The angular dependent yields of the ejected photoelectrons were determined using energy-and angle-resolved electron spectroscopy. The asymmetry parameter was found to be essentially constant at β 0.18 over the spectral range 1.78–2.09 eV

An investigation of Li− photodetachment in the vicinity of the 22 + ϵs threshold

Abstract A crossed laser-ion beam apparatus has been used to determine the electron affinity of Li and to measure cross sections for single photon-single electron detachment from Li − . Photoelectron production via the resolved 2 Sϵp and 2 Pϵs channels has been studied in detail in the vicinity of the 2 2 P+ϵs threshold. The electron affinity of Li − was found to be 617.6 ± 0.2 meV by threshold-photodetachment spectroscopy. Absolute cross sections and asymmetry parameters are also measured at discrete wavelengths in the spectral range of 1.78–2.50 eV.

Photodetachment of metastable He

Abstract A crossed-beams apparatus has been used to measure angular distributions and cross sections for photoelectron detachment from metastable He − . Energy- and angle-resolved electron spectroscopy was used to investigate the spectral dependences of the angular distribution of the photoelectrons. The angular distributions along with photoelectron yield measurements were used to determine the cross sections for photodetachment of He − (2 4 P) via the energy resolved He(2 3 P) and He(2 3 S) exit channels. The precision of the cross section measurements was enhanced by exploiting the kinematic effects associated with detachment from a fast beam source. Calculated cross sections for the photodetachment of H − were used to establish an absolute scale for the He − cross section measurements.