Measurements of absolute cross sections for the photoionisation of Ba+ions
- 28 December 1986
- journal article
- Published by IOP Publishing in Journal of Physics B: Atomic and Molecular Physics
- Vol. 19 (24) , 4137-4147
- https://doi.org/10.1088/0022-3700/19/24/015
Abstract
An apparatus is described in which merged beams of ground-state Ba+ ions and energy-resolved radiation from the Daresbury Synchrotron Radiation Source were used to obtain absolute cross sections for the photoionisation of Ba+ in the wavelength range 420-775 AA (29.5-16.0 eV). Approximately 75 peaks were resolved, the largest of which corresponded to cross sections greater than 10-15 cm2; this indicated very large contributions from inner-shell excitation-autoionisation. Systematic errors were estimated to be less than +or-15% and the energy resolution ranged between 20 and 4 meV. The energies of some of the peaks can be correlated closely with series limits of inner-shell transitions of neutral barium measured by Connerade et al. (1979) and with energies of autoionising states of Ba+ calculated by Hansen (1974-5) and by Griffin et al. (1984) in Hartree-Fock approximations. The energies of some transitions also correspond quite closely with absorption lines observed by Roig (1976) by flash pyrolysis of barium vapour.Keywords
This publication has 14 references indexed in Scilit:
- A robust, efficient surface ionisation sourceJournal of Physics E: Scientific Instruments, 1984
- Calculations of the contributions of excitation-autoionisation to the electron impact ionisation of Ca+and Ba+in the distorted-wave approximationJournal of Physics B: Atomic and Molecular Physics, 1984
- Evidence of autoionisation in the photoionisation of Ba+Journal of Physics B: Atomic and Molecular Physics, 1984
- Double ionisation in the region of the 5p thresholds of Ba and YbJournal of Physics B: Atomic and Molecular Physics, 1981
- Beam-scanning system for determination of beam profiles and form factors in merged-beam experimentsJournal of Physics E: Scientific Instruments, 1979
- A study of 5p excitation in atomic barium. I. The 5p absorption spectra of Ba 1, Cs 1 and related elementsPhilosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences, 1979
- Rapid determination of the overlap integral in a merging beams systemReview of Scientific Instruments, 1976
- The structure of the autoionizing p5ds configurations in Mg II, Ca II, Sr II and Ba II and interpretation of electron impact cross sections for these ionsJournal of Physics B: Atomic and Molecular Physics, 1975
- On the 584.3 AA photoelectron spectrum of BaJournal of Physics B: Atomic and Molecular Physics, 1975
- Identification of autoionization thresholds in the cross section for electron ionization of Ba+Journal of Physics B: Atomic and Molecular Physics, 1974