Geoscience Reference

In-Depth Information

Fig. 1.16

Theoretical results for the total chemo-ionization rate constants in hydrogen

Tabl e 1. 6
Values of the

coefficients of PI and AI

reactions at
T

k
PI
10
10

k
AI
10
10

cm
3

s
1

cm
3

s
1

States

D

450 K

7
2
S

0.5

0.6

5
2
D

1.7

Negligible

6
2
D1.4

7
2
D1.2

8
2
D1.0

9
2
D0.9

A difference between the values
k
PI
and
k
AI
is defined by the difference of

contributions of the direct and the reverse processes to the total autoionization

width for
n
2
Sand
n
2
D states of the excited atom. Qualitatively, this can be seen

in the experiments on the hydrogen chemoionization of the alkali atoms and the

calculations for the hydrogen atom (Fig.
1.16
). A quantum mechanical model of

the chemoionization was considered by Duman and Shmatov (
1980
). The power

dependence
n
max
T
½
,where
n
max
is the value of the principal quantum number,

corresponds to the maximum of the rate constant.

1.8.2

Asymmetrical Collisions

The signals corresponding to the excitation states
n
2
P of the sodium atoms present

as minor impurities at optical excitation of the potassium vapor, as reported by