Chemistry Reference
In-Depth Information
TABLE 3.8
Overview and the Classification of the Different Elementary Collision
Processes of
Heavy Particles
in the Plasma Volume
Ion processes
A
+
+B
→
A+B
+
Charge transfer (asymmetric, nonresonant)
26
A
+
+A
→
A+A
+
Charge transfer (symmetric, resonant)
27
A
m
+B
→
A+B
+
+
e
−
Penning ionization
28
→
AB
+
+
e
−
A
m
+A
m
→
A+A
+
+
e
−
Pair ionization
29
A
∗
+A
→
A
2
+
e
−
Hornbeck-Molnar (associative) ionization
30
A
+
+BC
→
AC
+
+ B
Ion-molecule reaction
31
A
+
+B
−
→
A + B
Ion-ion recombination
32
→
AB
A
−
+B
→
A+B+
e
−
Collisional detachment
33
A
−
+B
→
AB +
e
−
Associative detachment
34
Neutral processes
A
∗
+B
→
A+B
∗
Excitation transfer
35
AB
∗
+C
→
A + B + C
Dissociation
36
A+BC
→
AC + B
Chemical reactions
37
AB + CD
→
AC + BD
Two-body molecule reaction
AB + CD
→
ABC + D
R+BC
→
RC + B
Chemical reactions with radical
R
in the plasma
38
A
∗
+BC
→
AC + B
Chemical reactions with excited atom or molecule
39
A
+
BC + M
→
AB + C + M
Three-body reaction (or wall as third partner)
40
Photon processes
A+
h
ν
→
A
∗
Photoexcitation
41
A+
h
ν
→
A
+
+
e
−
Photoionization
42
AB +
h
ν
→
A + B
Photodissociation
43
A
∗
+
h
ν
→
A+
h
ν +
h
ν
Induced emission
44
Atom/Molecule
Radius a [Å]
He
1.15
a
2
a
1
+
a
2
Ar
1.43
H
2
1.38
N
2
1.57
a
1
O
2
1.45
CO
2.28
CO
2
1.61
σ
HS
H
2
O
1.44
FIGURE 3.15
Scheme of the hard sphere collision cross section and examples of gas
kinetic atom/molecule radius. (From Heinze, W.,
Einführung in die Vakuumtechnik, Vol.1:
Physikalische Grundlagen der Vakuumtechnik
, Verlag Technik, Berlin, Germany, 1955.)
