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Title: Absolute cross section for C{sup 2+}(2s2p {sup 3}P{sup o}{yields}2p{sup 2} {sup 3}P) electron-impact excitation

Abstract

We have measured the absolute energy-averaged cross section for the electron impact excitation of C{sup 2+}(2s2p {sup 3}P{sup o}{yields}2p{sup 2} {sup 3}P) from energies below threshold to 17 eV above, and present the measured absolute rate coefficients for this transition, for temperatures from 10{sup 4} to 10{sup 5} K. These rate coefficients are required for diagnostics of plasmas such as those found in astrophysical environments. The synchronous photon detection method with beams modulation and inclined electron and ion beams was used. Radiation at 117.6 nm from the decay of the excited ions back to the metastable state was detected using an absolutely calibrated optical system. The fractional population of metastable C{sup 2+}(2s2p {sup 3}P{sup o}) in the incident ion beam was determined to be 0.42{+-}0.03(1.65 {sigma}). The rate coefficient for log{sub 10} T=4.8 was determined to be 1.01x10{sup -8} cm{sup 3} s{sup -1}{+-}14% at a 90% confidence (1.65 {sigma}) level. The measured cross section is in agreement within experimental uncertainty with 6-term close-coupling R-matrix calculations and 90-term R matrix with pseudostates calculations.

Authors:
; ; ;  [1]
  1. Harvard-Smithsonian Center for Astrophysics, Cambridge, Masssachusetts 02138 (United States)
Publication Date:
OSTI Identifier:
20786915
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 73; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevA.73.032709; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; CARBON; CARBON IONS; CATIONS; COUPLING; CROSS SECTIONS; DECAY; DETECTION; ELECTRON-ATOM COLLISIONS; ELECTRONS; EV RANGE; EXCITATION; ION BEAMS; METASTABLE STATES; MODULATION; OPTICAL SYSTEMS; PHOTONS; PLASMA; R MATRIX

Citation Formats

Daw, A., Gardner, L. D., Janzen, P. H., and Kohl, J. L. Absolute cross section for C{sup 2+}(2s2p {sup 3}P{sup o}{yields}2p{sup 2} {sup 3}P) electron-impact excitation. United States: N. p., 2006. Web. doi:10.1103/PHYSREVA.73.0.
Daw, A., Gardner, L. D., Janzen, P. H., & Kohl, J. L. Absolute cross section for C{sup 2+}(2s2p {sup 3}P{sup o}{yields}2p{sup 2} {sup 3}P) electron-impact excitation. United States. doi:10.1103/PHYSREVA.73.0.
Daw, A., Gardner, L. D., Janzen, P. H., and Kohl, J. L. Wed . "Absolute cross section for C{sup 2+}(2s2p {sup 3}P{sup o}{yields}2p{sup 2} {sup 3}P) electron-impact excitation". United States. doi:10.1103/PHYSREVA.73.0.
@article{osti_20786915,
title = {Absolute cross section for C{sup 2+}(2s2p {sup 3}P{sup o}{yields}2p{sup 2} {sup 3}P) electron-impact excitation},
author = {Daw, A. and Gardner, L. D. and Janzen, P. H. and Kohl, J. L.},
abstractNote = {We have measured the absolute energy-averaged cross section for the electron impact excitation of C{sup 2+}(2s2p {sup 3}P{sup o}{yields}2p{sup 2} {sup 3}P) from energies below threshold to 17 eV above, and present the measured absolute rate coefficients for this transition, for temperatures from 10{sup 4} to 10{sup 5} K. These rate coefficients are required for diagnostics of plasmas such as those found in astrophysical environments. The synchronous photon detection method with beams modulation and inclined electron and ion beams was used. Radiation at 117.6 nm from the decay of the excited ions back to the metastable state was detected using an absolutely calibrated optical system. The fractional population of metastable C{sup 2+}(2s2p {sup 3}P{sup o}) in the incident ion beam was determined to be 0.42{+-}0.03(1.65 {sigma}). The rate coefficient for log{sub 10} T=4.8 was determined to be 1.01x10{sup -8} cm{sup 3} s{sup -1}{+-}14% at a 90% confidence (1.65 {sigma}) level. The measured cross section is in agreement within experimental uncertainty with 6-term close-coupling R-matrix calculations and 90-term R matrix with pseudostates calculations.},
doi = {10.1103/PHYSREVA.73.0},
journal = {Physical Review. A},
number = 3,
volume = 73,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}