Ad. Bass et al., ABSOLUTE CROSS-SECTION FOR DISSOCIATIVE ELECTRON-ATTACHMENT TO CF4 CONDENSED ONTO MULTILAYER KRYPTON, Journal of physical chemistry, 99(16), 1995, pp. 6123-6127
We present data showing the energy dependence of the electron-stimulat
ed desorption signal and charge-trapping cross section for molecules o
f CF4 condensed onto a multilayer Kr film. In both cases, these phenom
ena occur via dissociative electron attachment (DEA) to the molecule.
As with pure CF4 films, the only detectable desorbed signal from the f
ilm is F-, generated via the lowest of two CF4- resonant states associ
ated with DEA. However, both resonant states are implicated in charge
trapping via the formation of fragment ions at the surface. The charge
-trapping cross section at maximum, is 4-7 times greater than the cros
s section for DEA in the gas phase. The enhancement in the DEA cross s
ection is estimated to be between a factor 5 and 9. This enhancement r
eflects an increased probability of survival against autodetachment fo
r intermediate anion stares that results from interaction with-the ele
ctronic polarization field they induce on the Kr surface.