  Nonlocal potential models have been used in place of the Coulomb potential in
the Schrodinger equation as an efficient means of exploring high field
laser-atom interaction in previous works. Al- though these models have found
use in modeling phenomena including photo-ionization and ejected electron
momentum spectra, they are known to break electromagnetic gauge invariance.
This paper examines if there is a preferred gauge for the linear field response
and photoionization characteristics of nonlocal atomic binding potentials in
the length and velocity gauges. It is found that the length gauge is preferable
for a wide range of parameters.
