DOUBLY EXCITED STATES OF THE LiI ISOELECTRONIC SEQUENCE

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Submitted on 1 Jan 1979

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DOUBLY EXCITED STATES OF THE LiI ISOELECTRONIC SEQUENCE

K. To, E. Knystautas, R. Drouin, H. Berry

To cite this version:

K. To, E. Knystautas, R. Drouin, H. Berry. DOUBLY EXCITED STATES OF THE LiI ISOELECTRONIC SEQUENCE. Journal de Physique Colloques, 1979, 40 (C1), pp.C1-3-C1-5.

�10.1051/jphyscol:1979101�. �jpa-00218380�

JOURNAL DE PHYSIQUE

Colloque C1, supplkment au n o

2,

Tome

40,

fkvrier 1979, page C1-3

K.X. To,

E.

Knystautas, and

R.

Drouin Universite Laval, Quebec, Canada G l K 7P4

and

H.

G. Berry

Department of Physics, University of Chicago, Chicago, 60637 and Argonne National Laboratory, Argonne, 60439, USA

Rdsuml. Nous presentons les niveaux d'lnergie des systSmes multi-excitls de la sequence iso6lectronique 2 Li I, jusqu's Ne VIII. Les identifications sont basses sur de

recents experimentaux et theoriques, qui suggsrent une rlvision des termes

Abstract. We present the term level diagams of the doubly excited quartet systems of the L i I isoelectronic sequence up to NeVIII. The identifications are based on recent theoretical and experimental work which suggest a revision particular1 y, of the 2 ~ 3 ~

4 ~ 0

terms.

The three electron doubly-excited quartet system of been reclassified i n O V I where the data are taken from the L i I isoelectronic sequence has been extensively investi- several sourcesfb9 and recent unpublished work at gated using the beam f o i l technique.' However, identifi- Argonne. The reclassifications in fluorine and neon are cations have been hampered by low light intensities in most based mostly on work at ~ a v a l , ~ O f ' ~ but with comparable such transitions and by typically large line widths of the results by Pegg eta[.* i n fluorine and Buchet eta~.~inneon.

beam foil spectra. Several questions remain, the most out-

4

o standing of which i s the classification of the 2snp

P

(n23) levels for a l l isoelectronic sequence members. Crossley and other recent calculation2 suggest that earlier experimental identifications of the low members of the sequence of 2s3p

4 ~ 0

may be in error. Our results here for higher membersof the sequence tend to confirm the theoretical values, but only i n N V (see figure) are definite closed loops of transi- tions to this level observed. Our observations i n

B

I11 also suggest agreement with theory, but the relevant transitions are of very weak intensity and may possibly be blended.

We present below energy level diagams for the quartet terms for all ions L i I to NeVIII. The lines identi- fied are taken from many different sources. Thus, the LiI transitions are from the recent work sf Bromander et a l a 3 reported in this Conference. The Be I1 transitions are from Hontzeas et a1.4 and earlier work quoted therein. Note

4 o

that the

P

term has been reassigned. More wbrk in the vacuum ultraviolet spectra of lithium and beryllium i s

4 o needed to verify the theoretical predictions in the

P

terms.

The B I11 transitions are taken from

TO,^

and unpublished work at Edmonton (Berry and Pinnington) and at Lyon (Berry and Subtil). The carbon and nitrogen transitions have been measured recently at Argonne and Laval. Work

i s continuing on these spectra. Several transitions have

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1979101

JOURNAL DE PHYSIQUE

207.51(

d

( I S ~ ~ ~ ~ P O )

In future work, we shall include a more complete

l i s t

of energies, quantum defects and wavelengths for all ions

UD

to Ne VIII.

References

h his ^work

^{i s}

supported in part by the U.S. Department of Energy and the National Science Foundation.

1. H. G. Berry, Rep. Prog. Phys. 12, 5 (1975). -

2.

R. H. Crossley, These Proceedings and references therein.

3. J. Bromander et al., These Proceedings.

4. S. Hontzeas et al., Physica Scripta 6, 55 (1972). -

5. K. X. To, Ph.D. Thesis, Laval, 1978.

6. E. J. Knystautas and R. Drouin, J. Phys. B 8, 2001 -

(1 975).

7. F. Hannebauer, H. v. Buttlar, and P. H. Heckmann, Physics Scripta 17, 479 (1978). -

8. D. J. Pegg et al., Phys. Rev. A 1 - 0, 745 (1 974).

9. J. P. Buchet et al., B.F.S. Conf. V, p. 355 (1976).

10. D. J; G. Irwin and R. Drouin, B.F.S. Conf. V, p . 347 (1 976).

11. R. Barrette, Ph.D. Thesis, Laval, 1975.