Db. Milosevic et F. Ehlotzky, INFLUENCE OF SCREENING OF THE COULOMB POTENTIAL ON THE PLATEAU IN ABOVE-THRESHOLD IONIZATION, Physical review. A, 57(6), 1998, pp. 5002-5005
We present a generalization of the Keldysh-Faisal-Reiss model that inc
ludes the second-order S-matrix element and thus the effects of rescat
tering. On the example of a screened Coulomb potential we show that us
ing our model it is possible to reproduce all main features of the rec
ent experimental results, mainly, the appearance of a plateau, the pos
ition of the cutoff, and the side lobes. We also show that the differe
nce between the direct ionization probability and the rescattering pla
teau for a long-range Coulomb-like potential (with a small screening p
arameter) is very large, which is in discrepancy with the experimental
results. This indicates that the effective potential that an electron
feels during the rescattering is not a pure Coulomb potential. We sho
w that this potential can be approximated by a screened Coulomb potent
ial with a properly chosen screening parameter.