  Rescattering electrons offer great potential as probes of molecular
properties on ultrafast timescales. The most famous example is molecular
tomography, in which high harmonic spectra of oriented molecules are mapped to
``tomographic images'' of the relevant molecular orbitals. The accuracy of such
reconstructions may be greatly affected by the distortion of scattering
wavefunctions from their asymptotic forms due to interactions with the parent
ion. We investigate the validity of the commonly used plane wave approximation
in molecular tomography, showing how such distortions affect the resulting
orbital reconstructions.
