Geoscience Reference
In-Depth Information
Therefore, when is small, the electromagnetic field influence on the processes
(
2.1
,
2.2
,and
2.3
) must appear at the complex formation stage only, where Rydberg
electron dynamics is multichannel. The problem was analyzed in the one-channel
approximation by Giusti-Suzor and Zoller (
1987
), and multichannel treatment was
developed subsequently (He et al.
1989
;Ivanovetal.
1988
,
1995
,
1997b
,
c
,
1999
;
Vartazaryan et al.
1989
; Golubkov et al.
1993
; Golubkov and Ivanov
1993
,
1994
,
1997
). Note that the time-independent theory reported in references (Ivanov et al.
1988
,
1995
,
1997b
,
c
,
1999
; Vartazaryan et al.
1989
; Golubkov et al.
1993
,
1999a
,
b
;
Golubkov and Ivanov
1993
,
1994
.
1997
) automatically takes into account the Stark
effect.
Another limitation of the time-independent theory discussed here is imposed by
requiring that
f!
5=3
f
1;
(2.6)
which means negligible probabilities of the transitions between Coulomb contin-
uum states (Ivanov and Golubkov
1991
). Under these conditions, the field effect
on the complex
XY
**
is quantified in terms of the Rydberg resonance widths
n
q
.f!
5=
f
/
2
=n
q
,wheren
q
is the principal quantum number of the
q
th Rydberg
resonance series associated with a closed channel (index
q
subsumes the incident
angular momentum
l
, its projection ƒ on the molecular axis, and the set of the ion's
internal quantum numbers). The resonance width
n
q
should be compared with the
natural decay width
n
q
=n
q
, where the decay rate is
1, in line with the
concept of the existence of an intermediate complex. Accordingly, one criterion for
strong field effect on the intermediate state should be that
<
f!
5=3
f
2
1:
(2.7)
However, the external field can affect the complex
XY
**
at much lower intensities
f
if resonances of the different Rydberg series (for example, n
q
and n
0
q
0
)overlapor
happen to lie closely to one another. In this case, the field interaction between the
resonance states
.
n
q
n
0
q
0
3=2
;
V
n
q
n
0
q
0
f!
5=3
(2.8)
f
must be comparable with their half-widths or the level separation
n
q
n
0
q
0
D
ˇ
ˇ
ˇ
E
n
q
E
n
0
q
0
ˇ
ˇ
ˇ
(Golubkov et al.
1993
); i.e.,
8
<
n
q
;
n
0
q
0
; >;
n
q
n
0
q
0
; >:
V
n
q
n
0
q
0
(2.9)
:
