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The Measurement of Branching Ratios of Spontaneous Radiative Transition Probabilities for Be-Like Ions N IV and O V

Published online by Cambridge University Press:  12 April 2016

J. Lang ,
R.A. Hardcastle  and
P.H. Spurrett
J. Lang
Affiliation:
Space and Astrophysics Division, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire 0X11 OQX, UK
R.A. Hardcastle
Affiliation:
Space and Astrophysics Division, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire 0X11 OQX, UK
P.H. Spurrett
Affiliation:
Space and Astrophysics Division, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire 0X11 OQX, UK

Extract

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In an experiment to measure emission line intensities from the Belike ion Ne VII (Lang 1983), the intensity ratio I(2s3s3S−2s3p3P)/I(2p23P−2s3p3P) was found to be a factor six larger than predicted from the ratio of the theoretical spontaneous radiative transition probabilities (A values). Indeed, to reconcile the Ne VII experiment and theory in several respects it was suggested also that in Be-like C III the theoretical ratios I(2s3s1 S−2s3p1P)/I(2p21D−2s3p1P) was about a factor three too low.

The same apparatus was used to measure A value ratios in Be-like N IV and 0 V. Briefly the 40 kJ θ-pinch plasma source was viewed radially using a m Ebert and a l m grazing incidence photoelectric spectrometer. The m Ebert was intensity calibrated from 7300 Å to 3600 Å using a tungsten filament lamp, and from 3800 Å to 2500 Å using a deuterium lamp, both lamps having been calibrated by NPL. As described fully by Lang (1983), the branching-ratios method was used to calibrate the front exit slit of the grazing incidence instrument in the wavelength range 88 Å to 500 Å. Only Li-like line pairs of those listed in that paper were used with the addition of the C IV doublets 2s2S−3p2P (312.4 Å) and 3s2S−3p2P (5801.33 Å, 5811.98 Å). The H-like ion He II 1–4 transition (243.0 Å) and 3–4 transition (4685.7 Å) were used to cross-check the calibration. As shown in the figure, the He II result agrees excellently with the calibration as defined from the Li-like lines.

Type
Session 5. Experimental Atomic Physics
Information
International Astronomical Union Colloquium , Volume 86: Eighth International Colloquium on Ultraviolet and X-ray Spectroscopy of Astrophysical and Laboratory Plasmas , 1984 , pp. 125 - 127
Copyright
Copyright © Naval Research Laboratory 1984. Publication courtesy of the Naval Research Laboratory, Washington, DC.

References

(1.) Fawcett, B.C., 1984, Atomic Data and Nuclear Data Tables, 30, 1.CrossRefGoogle Scholar
(2.) Glass, R., 1979, J.Phys.B; At.Mol.Phys., 12, 1633.CrossRefGoogle Scholar
(3.) Glass, R., 1981, Z.Phys.A - Atoms and Nuclei, 299, 15.CrossRefGoogle Scholar
(4.) Hibbert, A., 1976, J.Phys.B; At.Mol.Phys., 9, 2805.CrossRefGoogle Scholar
(5.) Hibbert, A., 1980, J.Phys.B: At.Mol.Phys., 13, 1721.CrossRefGoogle Scholar
(6.) Hummer, D.G. and Norcross, D.W., 1974, Mon.Not.R.astr.Soc., 168, 263.CrossRefGoogle Scholar
(7.) Keenan, F.P., Berrington, K.A., Burke, P.G., Kingston, A.E. and Dufton, P.L., 1984, Mon.Not.R.astr.Soc., 207, 459.CrossRefGoogle Scholar
(8.) Lang, J., 1983, J.Phys.B: At.Mol.Phys., 16, 3907.CrossRefGoogle Scholar
(9.) Laughlin, C., Constantinides, E.R. and Victor, G.A., 1978, J.Phys.B: At.Mol.Phys., 11, 2243.CrossRefGoogle Scholar
(10.) Malinovsky, M., 1975, Astronomy & Astrophysics, 43, 101.Google Scholar
(11.) Nussbaumer, M., 1972, Astronomy & Astrophysics, 16, 77.Google Scholar