EXPLANATION OF RECENT OBSERVATIONS OF VERY LARGE ELECTROMAGNETIC DISSOCIATION CROSS-SECTIONS .2. HIGHER-ORDER CORRECTIONS

Hill, Wohn, Schwellenbach, and Smith have recently measured very large electromagnetic dissociation cross sections in the collisions of very heavy nuclei. Weizsacker-Williams (WW) theory predicts that these cro ss sections should be even larger. It has recently been shown that WW theory fails for these reactions because the associated probabilities are too large. However, WW theory is based on first order perturbation theory and an electric dipole approximation. Calculations are present ed which show that for those cases where WW theory and experiment disa gree, higher order perturbation plus electric quadrupole corrections i mprove the agreement between theory and experiment. These corrections also imply that multiple electromagnetic excitations occur.