Environmental Engineering Reference
In-Depth Information
a demonstration of this, Figure 2.14 gives the energy dependence for the cross
section of dissociative attachment of an electron to a CO
2
molecule [114] and Fig-
ure 2.15 contains the lower electronic states of the CO
2
molecule and its negative
molecular ion when the nuclei lie in one line. These electronic states are responsi-
ble for dissociative electron attachment to the CO
2
molecule [115].
Some collision processes of slow atomic particles are determined by transitions
of the quasimolecule consisting of colliding atomic particles in autoionizing or
autodetaching states. In this case an electronic state intersects the boundary of
continuous spectra at some distance between the colliding particles. In the region
of smaller distances, this state becomes the autoionizing or autodetaching state,
and the system of colliding particles can decay with the release of an electron. In
particular, the process of associative ionization, that is, the inverse process with
respect to dissociative recombination, proceeds according to the scheme
A
C
(
AB
)
!
AB
C
C
B
!
e
,
(2.74)
Figure 2.14
The cross section of dissociative
attachment of an electron to a CO
2
molecule
(
section at electron energies of 4.4 and 8.2 eV
correspond to positions of the autodetach-
ment levels of the negative ion CO
2
e
C
CO
2
!
O
C
CO) as a function of the
electron energy [114]. The maxima of the cross
.
Figure 2.15
The electronic states of the CO
2
molecule and its negative ion which are responsi-
ble for electron attachment to this molecule [115].
