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Title: Measurement of the partial photoionization cross sections and asymmetry parameters of S atoms in the photon energy range 10.0-30.0 eV using constant-ionic-state spectroscopy

Abstract

The partial photoionization cross sections and asymmetry parameters of S atoms have been measured using constant-ionic-state (CIS) spectroscopy in the photon energy range 10.0-30.0 eV. The ionizations investigated in these CIS experiments are the (3p){sup -1} ionizations S{sup +}({sup 4}S)(leftarrow)S({sup 3}P), S{sup +}({sup 2}D)(leftarrow)S({sup 3}P), and S{sup +}({sup 2}P)(leftarrow)S({sup 3}P). For the first time Rydberg series which converge to the fourth ionization limit have been observed and assignments of these series have been proposed. These correspond to excitations to Rydberg states that are parts of series which converge to the fourth ionization limit, S{sup +}({sup 4}P)(leftarrow)S({sup 3}P) (3s){sup -1}, and autoionize to the lower S{sup +}({sup 4}S), S{sup +}({sup 2}D), or S{sup +}({sup 2}P) states. For each series observed in the CIS spectra photoelectron angular distribution studies, combined with other evidence, has allowed the angular momentum character of the free electron on autoionization to be determined.

Authors:
; ; ; ; ; ;  [1];  [2];  [3];  [4];  [4];  [3]
  1. Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom)
  2. (Portugal)
  3. (United Kingdom)
  4. (Italy)
Publication Date:
OSTI Identifier:
20991248
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 126; Journal Issue: 15; Other Information: DOI: 10.1063/1.2720391; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; AUTOIONIZATION; CROSS SECTIONS; EV RANGE 10-100; PHOTOELECTRON SPECTROSCOPY; PHOTOIONIZATION; PHOTON-ATOM COLLISIONS; RYDBERG STATES; SPECTRA; SULFUR; SULFUR IONS

Citation Formats

Innocenti, Fabrizio, Zuin, Lucia, Costa, Maria L., Dias, Antonio A., Morris, Alan, Stranges, Stefano, Dyke, John M., CEFITEC, Department of Physics, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, Department of Chemistry, ISMN-CNR Sezione Roma La Sapienza I-00185, INSTM, Unita di Roma, La Sapienza, and Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ. Measurement of the partial photoionization cross sections and asymmetry parameters of S atoms in the photon energy range 10.0-30.0 eV using constant-ionic-state spectroscopy. United States: N. p., 2007. Web. doi:10.1063/1.2720391.
Innocenti, Fabrizio, Zuin, Lucia, Costa, Maria L., Dias, Antonio A., Morris, Alan, Stranges, Stefano, Dyke, John M., CEFITEC, Department of Physics, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, Department of Chemistry, ISMN-CNR Sezione Roma La Sapienza I-00185, INSTM, Unita di Roma, La Sapienza, & Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ. Measurement of the partial photoionization cross sections and asymmetry parameters of S atoms in the photon energy range 10.0-30.0 eV using constant-ionic-state spectroscopy. United States. doi:10.1063/1.2720391.
Innocenti, Fabrizio, Zuin, Lucia, Costa, Maria L., Dias, Antonio A., Morris, Alan, Stranges, Stefano, Dyke, John M., CEFITEC, Department of Physics, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, Department of Chemistry, ISMN-CNR Sezione Roma La Sapienza I-00185, INSTM, Unita di Roma, La Sapienza, and Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ. Sat . "Measurement of the partial photoionization cross sections and asymmetry parameters of S atoms in the photon energy range 10.0-30.0 eV using constant-ionic-state spectroscopy". United States. doi:10.1063/1.2720391.
@article{osti_20991248,
title = {Measurement of the partial photoionization cross sections and asymmetry parameters of S atoms in the photon energy range 10.0-30.0 eV using constant-ionic-state spectroscopy},
author = {Innocenti, Fabrizio and Zuin, Lucia and Costa, Maria L. and Dias, Antonio A. and Morris, Alan and Stranges, Stefano and Dyke, John M. and CEFITEC, Department of Physics, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica and Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ and Department of Chemistry, ISMN-CNR Sezione Roma La Sapienza I-00185 and INSTM, Unita di Roma, La Sapienza and Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ},
abstractNote = {The partial photoionization cross sections and asymmetry parameters of S atoms have been measured using constant-ionic-state (CIS) spectroscopy in the photon energy range 10.0-30.0 eV. The ionizations investigated in these CIS experiments are the (3p){sup -1} ionizations S{sup +}({sup 4}S)(leftarrow)S({sup 3}P), S{sup +}({sup 2}D)(leftarrow)S({sup 3}P), and S{sup +}({sup 2}P)(leftarrow)S({sup 3}P). For the first time Rydberg series which converge to the fourth ionization limit have been observed and assignments of these series have been proposed. These correspond to excitations to Rydberg states that are parts of series which converge to the fourth ionization limit, S{sup +}({sup 4}P)(leftarrow)S({sup 3}P) (3s){sup -1}, and autoionize to the lower S{sup +}({sup 4}S), S{sup +}({sup 2}D), or S{sup +}({sup 2}P) states. For each series observed in the CIS spectra photoelectron angular distribution studies, combined with other evidence, has allowed the angular momentum character of the free electron on autoionization to be determined.},
doi = {10.1063/1.2720391},
journal = {Journal of Chemical Physics},
number = 15,
volume = 126,
place = {United States},
year = {Sat Apr 21 00:00:00 EDT 2007},
month = {Sat Apr 21 00:00:00 EDT 2007}
}
  • Relative partial photoionization cross-sections and angular distribution parameters, {beta}, have been measured for the first, I{sup +}({sup 3}P{sub 2})<-I({sup 2}P{sub 3/2}), and fourth, I{sup +}({sup 1}D{sub 2})<-I({sup 2}P{sub 3/2}), (5p){sup -1} photoelectron (PE) bands of atomic iodine, by performing angle-resolved constant-ionic-state (CIS) measurements on these PE bands in the photon energy range 11.0-23.0 eV. Three Rydberg series, two ns and one nd series, which converge to the I{sup +} {sup 3}P{sub 1} limit at 11.33 eV and four Rydberg series, two ns and two nd series, which converge to the I{sup +} {sup 1}D{sub 2} limit at 12.15 eV weremore » observed in the first PE band CIS spectra. The fourth band CIS spectrum showed structure in the 12.9-14.1eV photon energy range, which is also seen in the first band CIS spectra. This structure arises from excitation to ns and nd Rydberg states that are parts of series converging to the I{sup +} {sup 1}S{sub 0} limit we reported on earlier, as well as 5s{yields}5p excitations in the photon energy range 17.5-22.5 eV. These atomic iodine CIS spectra show reasonably good agreement with the equivalent spectra obtained for atomic bromine. The {beta}-plots for the first PE band recorded up to the I{sup +} {sup 3}P{sub 1} and I{sup +} {sup 1}D{sub 2} limits only show resonances corresponding to some of the 5p{yields}nd excitations observed in the first band CIS spectra scanned to the I{sup +} {sup 1}D{sub 2} limit (12.15 eV). These plots are interpreted in terms of an angular momentum transfer model with the positive values of {beta} obtained on resonances corresponding to parity allowed j{sub t}=1 and 3 channels and the off-resonance negative {beta} values corresponding to parity unfavored channels, where j{sub t} is the quantum number for angular momentum transfer between the molecule, and the ion and photoelectron. The {beta}-plots recorded for iodine are significantly different from those obtained for atomic bromine. Comparison of the experimental CIS spectra and {beta}-plots with available theoretical results highlights the need for higher level calculations which include factors such as configuration interaction in the initial and final states, relativistic effects including spin-orbit interaction, and autoionization via resonant Rydberg states.« less
  • Cross sections for the photoionization (PI) of Sc{sup 2+} ions with [Ar]3d ground-state configuration have been measured by employing the merged ion-photon beams method. The Sc{sup 2+} ions were produced from metallic vapor in an electron cyclotron resonance ion source, and the photon beam was generated by an undulator in the electron-synchrotron storage ring of the advanced light source of the Lawrence Berkeley National Laboratory. The experimental photon energy range 23-68 eV encompasses the direct 3d and 3p photoionization thresholds. The experimental photoion spectrum is dominated by autoionizing resonances due to 3p excitations predominantly decaying via Coster-Kronig and super-Coster-Kronig transitions.more » Individual resonances located around E{approx_equal}40.2 eV have been measured with an instrumental energy spread {delta}E as low as 1.2 meV, corresponding to a resolving power of E/({delta}E) around 33 500. The fractions of metastable ions in the Sc{sup 2+} ion beam are obtained by comparing the photoionization cross section with the recently measured [Schippers et al., Phys. Rev. A 65, 042723 (2002)] cross section for the time-reversed process of photorecombination of Sc{sup 3+} ions. Absolute strengths of several 3p{sup 5} 3d{sup 2} and 3p{sup 5} 3d 4s PI resonances have been determined. They are the same as the corresponding resonance strengths for isoelectronic Ca{sup +} ions.« less
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