The study of 3s3p4 configuration in the P-Sequence, Co XIII - Ni XIV, by laser-produced plasmas

Abstract

Wavelengths from radiation of plasmas produced by a Nd:YAG/glass laser focused on target of Co and Ni have been recorded photographically in the region 240-600 Å with a 3m normal incidence spectrograph. For this sequence (Co XIII and Ni XIV) we have identified 13 new lines belonging to the array 3s²3p³-3s3p4 and derived 7 new levels for the 3s3p4 configuration. The classification was established by comparison of the relative intensities for the lines along the isoelectronic sequence, extrapolation, and Hartree-Fock calculation.

Co XIII spectrum; Ni XIV spectrum; Laser-produced plasmas

REGULAR ARTICLES

The study of 3s3p⁴ configuration in the P-Sequence, Co XIII - Ni XIV, by laser-produced plasmas

F. O. Borges; G. H. Cavalcanti; E. E. Farias; A. G. Trigueiros

Instituto de Física, Universidade Federal Fluminense, UFF Campus da Praia Vermelha-Gragoatá, 24210-340 Niterói, Rio de Janeiro, Brazil

ABSTRACT

Wavelengths from radiation of plasmas produced by a Nd:YAG/glass laser focused on target of Co and Ni have been recorded photographically in the region 240-600 Å with a 3m normal incidence spectrograph. For this sequence (Co XIII and Ni XIV) we have identified 13 new lines belonging to the array 3s²3p³-3s3p⁴ and derived 7 new levels for the 3s3p⁴ configuration. The classification was established by comparison of the relative intensities for the lines along the isoelectronic sequence, extrapolation, and Hartree-Fock calculation.

Keywords: Co XIII spectrum; Ni XIV spectrum; Laser-produced plasmas

I. INTRODUCTION AND EXPERIMENT

The ground configuration of the P-like system is 3s²3p³ and has ⁵S₀ for the lowest energy level. For this sequence the spectra from P I to Fe XII are known[1] for the configuration 3s3p⁴. For more higher ionized ion in the P-isoelectronic sequence, no information was available. The purpose of this work is to study the energy levels structure of the 3s3p⁴ configuration in the P-sequence, Co XIII and Ni XIV.

We used the plates from an early experiment made by Litzén and Redfors.[2-3] In the same plates were presented lines from a recent work by Trigueros et al.[4] The spectra were obtained by focusing high-power pulses from a Quantel NG 24 Nd:YAG/glass laser into metal targets of the elements Co and Ni. The energy of the pulses was 4J to Co and Ni and had a duration of 3 nsec. A 3 m normal incidence spectrograph, with a grating of 1200 grooves/mm was used to recorder the radiation emitted by the plasma in a direction parallel to the target plane and perpendicular to the main direction of the plasma expansion, thus minimizing the Doppler effect from plasma mass motion. Spectra were recorded on Kodak 101 plates in the region 240-600 Å . The plate factor was 2.7 Å /mm. The estimated uncertainty of the wavelengths is about ± 0.05 Å .

II. WAVELENGTHS AND ENERGY LEVELS

In table 1 and 2 we show the wavelengths and energy levels for the Co XIII and Ni XIV ions in the phosphorus. We have studied the transitions 3s²3p³-3s3p⁴ in both ions and determined the energy levels in the 3s3p⁴ configuration. The classification of the lines was based on Hartree-Fock calculations and for this purpose we have used the Cowan's[5] computer code. In Fig. 1 we can see the extrapolation of the experimental energy level values from Ca VI to Ni XIV using the Edlén's[6] method. This method was also used to help the classification of the lines. The zero level in the figure 1 is the 3s²3p² level from the ground configuration. The net core charge is represented by z and 1.0 is a constant determined from the experimental energy levels in the extrapolation so that we can get a good smooth of the curve in the Fig. 1.

In an early analysis made by Fawcett and Hayes[7] some lines and energy levels were determined. In the present work we have classified 13 new lines belong the transition array 3s²3p³-3s3p⁴ and located 7 new levels to the 3s3p⁴ configuration. The transition 3s²3p³-3s3p^{4 4}P_5/2 at 316.53 Å in Ni XIV was classified by Fawcett and Hayes[7] but instead we present a new line at 316.12 Å. This new line is in agreement with our extrapolation and relative intensities along the isoeletronic sequence. We determined all levels for the 3s3p⁴ configuration in Co XIII and Ni XIV.

The results of calculations made by Huang[8] and Biémont[9] were available in the analysis of data from P-sequence.

Acknowledgements

This work has been supported by the Conselho Nacional de Desenvolvimento Cientí fico e Tecnológico, CNPq (Brazil) and Swedish Natural Science Research Council, NFR (Sweden). F. O. Borges, thanks Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro, FAPERJ (Brazil), for a fellowship.

Received on 17 November, 2006

• [1] R. L. Kelly, J. Phys. Chem. Ref. Data 16, 298 (1987).
• [2] U. Litzén and A. Redfors, Phys. Scr. 36, 895 (1987).
• [3] A. Redfors and U. Litzén, J. Opt. Soc. Am. B 6, 1447 (1989).
• [4] A. G. Trigueiros, F. O. Borges, G. H. Cavalcanti, and E. E. Farias, J. Quant. Spectrosc. Radiat. Transfer 97, 29 (2006).
• [5] R. D. Cowan, The Theory of Atomic Structure and Spectra, Berkeley: Univ. California Press (1981).
• [6] B. Edlén, Atomic Spectra in Encyclopedia of Physics, Edited by S. F. Flügge (Springer-Verlag, Berlin) vol. XXVI, 80(1984).
• [7] B. C. Fawcett and R. W. Hayes, J. Phys. B 5, 366 (1972).
• [8] K. N. Huang, Energy-Level Scheme and Transition-Probabilities of P-Like Ions, At. Data. Nucl. Data Tables 30, 313 (1984).
• [9] E. Biémont, Phys. Scr. 33, 324 (1986).

Publication Dates

• Publication in this collection
  17 July 2007
• Date of issue
  June 2007

History

• Received
  17 Nov 2006