The validity domain of a recently proposed iterative scheme for the in
version of the wavefunction of fast electrons after dynamical diffract
ion in a crystal, which is based on re versal of the multislice algori
thm, is investigated by Bloch wave analysis. It is shown that the sche
me fails when the thickness of the crystal is such that the scattering
is sufficiently strong for dominant Bloch wave structure to appear in
the wavefunction. The scheme could still be useful, however, in exten
ding the range of interpretable resolution and specimen thickness for
which electron scattering can be applied to crystal structure analysis
.