Bee al a eee led
3 a antDiaa
208
Ttot =
= {0.536 E ( e x) _ =|
+ 5.22 + 003] x 10°" em’,
Texe
z
~
s
o.
+ 293 4 006) x 10°” em’.
2
+299 + 003| x 10°° em
TABLE 71.
(7a)
These cross sections—actually «8'/z—are plotted
against In [8°/(1 — 8°)] — 6° in Figure 163, along with
(7b)
2
?
the Bethe cross section for the 2’P excitation.
Parameters ror tHE Betue Cross Sections ror Discrete Excitatron oF Lit
Allowed transition (nP)
n
Forbidden transition
M2
Cr
b(#lS)
b(n'D)
2
3
4
0.0998
0.0216
0.0082
0.835
0.183
0.069
0.022
0.005
0.002
0.002
0.001
n> 5)
0.461 + 1.09
3.95
8.04
0.105 4 0.148
0.0752 _ 0.135
(n*)?
(n*)*
(n*)5
(n*)8
(n*)6
(n*)5
{n*)8
Xs
0.0118
0.100
0.003
0,002
Do
0.1414
1.187
0.032
0.005
allan
(7e)
(n*)5
(a) The sum of 0(n!F) and higher excitations is estimated at ~1% of Sb (nD), and is neglected in evaluating Cexo.
()) n* = n+ 6, whereé = —0.074, 0.0136 and —0.001 for the 1S, 1P and 1D states, respectively.
INCIDENT ELECTRON ENERGY(keV)
T
-5
T
5
rey
10
|
20
-4
pe\
In (=) -B
Fic. 163.—The Bethe cross sections of Lit. The ordinate is the cross section * (@/z)?, where 8 = v/c is the velocity in units of
the speed of light and ze is the charge of the incident particle. The squares are the experimental data by Lineberger, Hooper, and
McDaniel,“the circles are those by Peart and Dolder,“* and the triangles are more recent data also by Peart and Dolder.“
Only representative error limits are shown for the experimental data. The error limits for the theoretical cross sections given at
In [62/(1 — 6*)] — 8? = —3 are independent of incident energy, contrary to the tendency in experiment.