  Kapitza-Dirac-Talbot-Lau interferometry (KDTLI) has recently been established
for demonstrating the quantum wave nature of large molecules. A phase space
treatment permits us to derive closed equations for the near-field interference
pattern, as well as for the Moire-type pattern that would arise if the
molecules were to be treated as classical particles. The model provides a
simple and elegant way to account for the molecular phase shifts related to the
optical dipole potential as well as for the incoherent effect of photon
absorption at the second grating. We present experimental results for different
molecular masses, polarizabilities and absorption cross sections using
fullerenes and fluorofullerenes and discuss the alignment requirements. Our
results with C60 and C70, C60F36 and C60F48 verify the theoretical description
to a high degree of precision.
