EGAS41 - Swansea University

41 st EGAS CP 182 Gdańsk 2009
K-X-ray hypersatellite intensity ratios and lifetimes
of the doubly K-shell ionized states
K. S̷labkowska 1,∗ , M. Polasik 1 , K. Kozio̷l 1 , J. Starosta 1 , J. Rzadkiewicz 2 , J.-Cl. Dousse 3 ,
Z. Sujkowski 2
1 Faculty of Chemistry, Nicolaus Copernicus University, 87-100 Toruń, Poland
2 Andrzej Soltan Institute for Nuclear Studies, 05-400 Świerk, Poland
3 Physics Department, University of Fribourg, CH-1700 Fribourg, Switzerland
∗ Corresponding author: katarzyna.slabkowska@uni.torun.pl
In the last decades the K h α 1,2 hypersatellite lines in the X-ray spectra were measured by
using different experimental techniques. High-resolution measurements of such spectra
[1, 2, 3] give direct access to the studies of the K-shell hollow (i.e. doubly K-shell ionized)
atoms. The present work provides the interpretation of the spectra for the K-shell hollow
atoms based on the advanced theoretical analysis of the K h α 1,2 hypersatellite lines. The
de-excitation of the doubly K-shell ionized state via the K h α 1 transition is forbidden in
the pure LS coupling scheme (the spin flip 1 S 0 → 3 P 1 ) but allowed in the j-j coupling
scheme (see Fig. 1).
K −2
LS
[ 1 S 0 ]
j-j
[1s −2
1/2 ] J=0
K h α 2 K h α 1
K −1 L −1
❄
❄
[ 1 P 1 ]
[ 3 P 1 ]
[1s −1
1/2 2p−1 1/2 ] J=1
[1s −1
1/2 2p−1 3/2 ] J=1
Figure 1: K h α 1,2 hypersatellite X-ray transitions.
As a result, the I(K h α 1 )/I(K h α 2 ) intensity ratio changes with the atomic number from
small values (for the LS coupling limit at low Z) to large values (for the j-j coupling limit
at high Z). It has been found that although the intensity ratios of the corresponding lines
demonstrate strong hindrance of the K h α 1 transitions for low Z, the lifetimes of doubly
K-shell ionized states do not lengthen in any case (i.e. they are always two times shorter
than for single K-shell ionized states). The effect is explained as a result of significant
mixing of the 3 P 1 and 1 P 1 states (in the LS coupling). The obtained theoretical results
are in agreement with experimentally observed data.
Acknowledgment
This work was supported by the Polish State Committee for Scientific Research under Grant
No. N N202 1465 33.
References
[1] B. Boschung et al., Phys. Rev. 51, 3650 (1995)
[2] J. Rzadkiewicz et al., Phys. Lett. A 264, 186 (1999)
[3] J. Rzadkiewicz et al., Nucl. Instr. and Meth. in Phys. Res. B 235, 110 (2005)
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