  We present a classical approximation for the peaks of survival resonances
occurring when diffracting matter waves from absorption potentials. Generally
our simplified model describes the absorption-diffraction process around the
Talbot time very well. Classical treatments of this process are presently
lacking. For purely imaginary potentials, the classical model duplicates
quantum mechanical calculations. The classical model allows for simple
evolution of phase-space probability densities, which in the limit of the
effective Planck's constant going to zero allows for a compact analytical
expression of the survival probability as a function of remaining parameters.
Our work extends the range of processes that can be described through classical
analogues.
