  The photon energy dependence of angle-resolved photoemission data on
Ca_2CuO_2Cl_2 is presented, and the role of the matrix element is investigated.
It is shown that despite strong variations in the matrix element, the loss in
intensity as one crosses the antiferromagnetic zone boundary is a robust
feature of the Mott insulator. As expected for a two dimensional system, the
dispersion remains independent of the photon energy even when the matrix
element does not.
