 |
Unless otherwise stated this page contains Version 1.0 content (Read more about versions)
4.4.6 Electron collisions
Observed total collision
cross-section of electrons with atoms and molecules
Q is the total collision cross-section in units
of π α , where α0 is the
radius of the first Bohr orbit of the hydrogen atom; α0 = 0.53
× 10−10 m. Hence the unit of Q in the tables
below is 0.88 × 10−20 m2. The values are
obtained by interpolation from graphs. General references:
Landolt–Bornstein Tables (1950); Massey and Burhop (1952). For
molecules, the data given relate to the Ramsauer method.
Q in units of π α
|
Gas |
(Energy)1/2/V1/2 |
|
0.5 |
1 |
1.5 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
|
H . .
. . . .
|
—
|
—
|
—
|
—
|
—
|
6
|
|
7
|
.6
|
8
|
.6
|
9
|
.0
|
—
|
—
|
—
|
|
H2 . .
. . . . |
— |
15 |
|
17 |
|
16 |
|
10 |
.5 |
7 |
|
5 |
.5 |
4 |
|
3 |
.5 |
— |
— |
— |
|
He . .
. . . . |
6 |
.3 |
6 |
.3 |
6 |
.2 |
5 |
.6 |
4 |
.6 |
3 |
.5 |
2 |
.6 |
2 |
.0 |
1 |
.7 |
1 |
.5 |
1 |
.3 |
1 |
.2 |
|
N2 . .
. . . . |
17 |
|
10 |
|
29 |
|
13 |
|
12 |
|
12 |
.5 |
14 |
|
13 |
|
11 |
.5 |
— |
— |
— |
|
O2 . .
. . . . |
6 |
|
7 |
|
7 |
.5 |
8 |
|
11 |
|
12 |
|
12 |
|
12 |
|
— |
— |
— |
— |
|
CO . . .
. . . |
15 |
|
14 |
|
38 |
|
18 |
|
14 |
|
14 |
|
14 |
|
— |
— |
— |
— |
— |
|
Ne . .
. . . . |
1 |
.0 |
1 |
.9 |
2 |
.5 |
2 |
.8 |
3 |
.5 |
3 |
.7 |
3 |
.7 |
3 |
.6 |
3 |
.5 |
3 |
.4 |
3 |
.0 |
2 |
.9 |
|
Na . .
. . . . |
— |
280 |
|
380 |
|
180 |
|
130 |
|
110 |
|
85 |
|
65 |
|
50 |
|
48 |
|
46 |
|
35 |
|
|
Ar . .
. . . . |
0 |
.6 |
0 |
.6 |
4 |
.0 |
8 |
.5 |
21 |
|
22 |
|
15 |
|
11 |
|
8 |
|
7 |
.5 |
7 |
|
6 |
.5 |
|
K . .
. . . . |
— |
450 |
|
420 |
|
270 |
|
220 |
|
160 |
|
125 |
|
80 |
|
60 |
|
50 |
|
50 |
|
40 |
|
|
Zn . .
. . . . |
— |
— |
— |
80 |
|
45 |
|
35 |
|
27 |
|
24 |
|
23 |
|
23 |
|
23 |
|
21 |
.5 |
|
Kr . .
. . . . |
2 |
.0 |
1 |
.0 |
6 |
.0 |
15 |
|
30 |
|
29 |
|
20 |
|
14 |
|
11 |
.5 |
9 |
|
8 |
|
7 |
.5 |
|
Rb . .
. . . |
— |
374 |
|
390 |
|
329 |
|
220 |
|
170 |
|
142 |
|
85 |
|
68 |
|
51 |
|
45 |
|
43 |
|
|
Cd . .
. . . . |
— |
— |
— |
— |
54 |
|
43 |
|
40 |
|
41 |
.5 |
39 |
|
34 |
|
31 |
|
29 |
|
|
Xe . .
. . . . |
7 |
.5 |
2 |
.0 |
15 |
|
33 |
|
43 |
|
32 |
.5 |
22 |
.5 |
16 |
|
— |
— |
— |
— |
|
Cs . .
. . . . |
— |
470 |
|
675 |
|
350 |
|
300 |
|
230 |
|
160 |
|
135 |
|
100 |
|
80 |
|
67 |
|
46 |
|
|
Hg . .
. . . . |
— |
80 |
|
70 |
|
55 |
|
23 |
|
18 |
|
18 |
|
20 |
|
20 |
|
18 |
.5 |
18 |
|
17 |
.5 |
|
Tl . .
. . . . |
— |
6 |
|
10 |
|
16 |
|
12 |
.5 |
11 |
|
9 |
.5 |
9 |
.0 |
8 |
.8 |
8 |
.0 |
7 |
.0 |
6 |
.2 |
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Cross-section
(Q) for ionization by electron impact
Q is
expressed in units of π α (i.e. 0.88 × 10−20 m2) for
removal of the first electron
|
Gas
|
Energy/V |
|
20 |
50 |
100 |
200 |
300 |
400 |
500 |
700 |
1000 |
2000 |
5000 |
|
H2 .
. . . .
. . . .
|
0.34
|
1.1
|
1.1
|
0.82
|
0.68
|
0.55
|
0.45
|
0.34
|
0.25
|
0.12
|
0.06
|
|
He . .
. . . .
. . . |
0 |
0.28 |
0.42 |
0.38 |
0.31 |
0.26 |
0.22 |
0.18 |
0.14 |
0.08 |
0.04 |
|
N2 .
. . . .
. . . . |
0.32 |
2.2 |
2.8 |
2.5 |
2.2 |
1.9 |
1.6 |
1.3 |
1.0 |
0.51 |
0.23 |
|
O2 .
. . . .
. . . . |
0.42 |
2.4 |
3.2 |
2.8 |
2.5 |
2.1 |
1.9 |
1.5 |
1.2 |
0.60 |
0.30 |
|
CO . .
. . . .
. . . |
|
2.9 |
3.5 |
3.0 |
2.4 |
2.0 |
1.8 |
|
|
|
|
|
NO . .
. . . .
. . . |
|
2.9 |
3.7 |
3.2 |
2.7 |
2.5 |
2.0 |
|
|
|
|
|
Ne . .
. . . .
. . . |
0 |
0.41 |
0.75 |
0.85 |
0.77 |
0.68 |
0.60 |
0.48 |
0.38 |
0.23 |
0.11 |
|
Ar . .
. . . .
. . . |
0.75 |
3.2 |
3.3 |
2.5 |
2.0 |
1.6 |
1.4 |
1.1 |
0.88 |
0.48 |
0.23 |
|
Kr . .
. . . .
. . . |
1.4 |
4.3 |
4.8 |
4.0 |
3.2 |
2.8 |
2.5 |
1.9 |
1.5 |
0.85 |
0.34 |
|
Xe . .
. . . .
. . . |
4.0 |
7.4 |
8.5 |
5.7 |
4.6 |
4.0 |
3.4 |
2.8 |
2.3 |
1.5 |
0.68 |
|
Hg . .
. . . .
. . . |
3.0 |
5.8 |
6.3 |
5.5 |
4.7 |
4.1 |
3.6 |
3.0 |
2.3 |
1.4 |
0.68 |
|
|
|
|
|
|
|
|
|
|
|
|
|
Data mainly from Tawara and Kato
(1987).
J.W. Leake
References
S. F. Biagi (1989) Nuclear Instruments and
Methods, A283, 716–722.
A. J. Blanc (1908) J.
Physique, 7, 825.
L. G. Christophorou et al. (1979)
Nuclear Instruments and Methods, 163, 141–149.
H. W.
Ellis et al. (1976) Atomic Data and Nuclear Data Tables,
17, 177–210.
Ibid. Part II (1978) 22,
179–217.
Ibid. Part III (1984) 31, 113–151.
G. W. Fraser and E. Mathieson (1987) Nuclear Instruments and Methods in
Physics Research, A257, 339–345.
R. H. Healey and J. W.
Reed (1941) The Behaviour of Slow Electrons in Gases, Amalgamated
Wireless Ltd,
Sydney.
L. G. H.
Huxley et al. (1959) Australian Journal of Physics, 12,
303.
Landolt–Bornstein Tables (1950) Vol. I,
Springer-Verlag.
L. B. Loeb (1955) Basic Processes of Gaseous
Electronics, California University Press, 477 et seq.
E. W.
McDaniel (1964) Collision Phenomena in Ionized Gases, Wiley, London.
H. S. W. Massey and E. H. S. Burhop (1952) Electronic and Ionic Impact
Phenomena, Oxford University Press.
T. Nagy et al. (1960)
Nuclear Instruments and Methods, 8, 327–330.
J. L.
Pack, R. E. Voshall and A. V. Phelps (1962) Physical Review, 127,
2084–2089.
V. Palladino and B. Sadoulet (1975) Nuclear Instruments
and Methods, 128, 323–335.
B. Schmidt and K. Martens
(1992) Nuclear Instruments and Methods in Physics Research, A317,
148–154.
H. Tawara and T. Kato (1987) Atomic Data and Nuclear Data
Tables, Academic Press, 36, 167–353.
A. M. Tyndall (1938)
Mobility of Positive Ions in Gases, Cambridge University Press.
J.
Va’vra (1992) Nuclear Instruments and Methods in Physics Research,
A323, 34–47.
|
|
