EGAS41 - Swansea University

41 st EGAS CP 190 Gdańsk 2009
Reorientation, alignment and coherence effects in Ca-RG
collisions
E. Paul-Kwiek
Institute of Physics, Pomeranian University in S̷lupsk, ul. Arciszewskiego 22,
76-200 S̷lupsk, Poland
∗ Corresponding author: ewa@.apsl.edu.pl,
The main purpose of the present work is to perform a detailed analysis of the alignment,
orientation and coherence effects in Ca(4s4p, 3 P j ) colliding with rare gas (RG) atoms.
The calculations are based on the standard close-coupling formalism (used for example
in [1,2]) with application the relevant pseudopotential curves of Czuchaj, Krośnicki, Stoll
[3].
σ ( 3 P j1 -> 3 P j2 ) [10 -16 cm 2 ]
40
Ca-He 1->2
0->2
30
2->1
20
0->1
10
2->0
1->0
0
0 .2 .4 .6 .8
σ ( 3 P j1
-> 3 P j2
) [10 -16 cm 2 ]
40
30
20
10
0
Ca-Xe
1->0
1->2
2->1
0->2
0->1
2->0
0 .2 .4 .6 .8
Ek[eV]
Ek[eV]
Figure 1: Total integral cross-section for the Ca(4s4p, 3 P j1 − > 3 P j2 ) spin changing transitions
induced by He and Xe as a function of translational energy.
The reorientation effect and angular distribution of scattered calcium atoms associated
with the inelastic transition j 1 m 1 → j 2 m 2 are discussed via multi-structure differential
cross-sections
dσ m1 →m 2
(j 1 → j 2 ;k j1 ,R))
dΩ
= k j 2
k j1
| f j1 m 1 →j 2 m 2
(k j1 ,R) | 2 , (1)
where f j1 m 1 →j 2 m 2
is the scattering amplitude and the vectors k j1 and R define the incident
velocity and the scattering directions, respectively. The alignment effects are described
by means of the conventional and coherence cross-sections
σ m1 m ′ 1 →m 2m ′ 2 (j 1 → j 2 ;k j1 ) = k j 2
k j1
∫
dˆRf j1 m 1 →j 2 m 2
(k j1 ,R) · f ∗ j 1 m ′ 1 →j 2m ′ 2 (k j 1
,R). (2)
References
[1] E. Paul-Kwiek, J. Phys. B At. Mol. Opt. Phys. 34, 285, (2001)
[2] E. Paul-Kwiek, J. Phys. B At. Mol. Opt. Phys. 35, 175, (2002)
[3] E. Czuchaj, M. Krośnicki, H. Stoll, Chemical Physics 292, 101 (2003)
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