Environmental Engineering Reference
In-Depth Information
For another limiting case,
[
C
](
k
q
C
k
d
)
1 ,
(2.106)
the number density of particles
C
is so high that the rate constant for formation of
the bound state
A
C
B
does not depend on this number density, and the formation
of the bound state
A
C
B
can be considered to be two body in nature with rate
constant
k
c
k
q
k
q
k
D
K
[
C
]
D
.
(2.107)
C
k
d
Particles
C
affect the factor
k
q
/(
k
q
k
d
) in (2.107), which is the probability that
collision of autodetaching ion (
A
C
B
)
and particle
C
leads to formation of the
bound state
AB
C
.
C
Ta b l e 2 . 19
Collision processes involving ions.
Process
Scheme
Comment number,
section of [146]
A
C
C
A
C
C
Elastic ion-atom
collisions
B
!
B
Section 2.1.9
A
C
C
A
C
Resonant charge
exchange
A
!
A
C
Section 2.1.9
A
C
C
B
C
a
,
b
Nonresonant charge
exchange
B
!
A
C
A
C
C
B
!
Mutual neutralization
of ions
A
C
B
Section 2.3.6
B
!
Decay of negative ions
A
C
AB
C
e
B
!
in atomic collisions
A
C
A
C
B
C
e
Section 2.2.4
A
C
C
AB
C
C
C
C
)
c
Ion-molecule
reactions
BC
!
C
(
AB
C
A
C
C
AB
C
C
B
C
C
!
C
Conversion of atomic
ions to molecular ions
in three body
collisions
Section 2.3.2
A
C
C
B
C
d
, Section 4.4.7
Ion-ion recombination
in three body
collisions
C
!
A
C
B
C
C
a
The cross section of the process is larger than the gas-kinetic cross section.
b
The cross section depends on the value of the Massey parameter.
c
These reactions are akin to chemical reactions.
d
At thermal collision energies, the rate constant of this process is of the order of 10
31
cm
6
/s.
Formation of an autodetaching state (
AB
C
)
in the course of the collision can result in this
value being exceeded by several orders of magnitude.
