CALCULATIONS ON THE GIANT-DIPOLE RESONANCE IN THE CONTINUUM RANDOM-PHASE-APPROXIMATION WITH A MOMENTUM-DEPENDENT INTERACTION

A formulation of the continuum random-phase approximation (CRPA) nucle ar response with a velocity-dependent residual interaction of the Skyr me type is presented. The inhomogeneous coupled-channel integro-differ ential equations obtained are modified so as to use the Lanczos method , by means of which they can be solved relatively easy. The CRPA metho d here presented can give information on the direct and statistical de cay as well as their partial ph components. We apply the method to a d etailed analysis of photonuclear reactions in He-4, O-16 and Ca-40 in the giant-dipole-resonance region. Total cross sections, contributions from direct emission and spreading as well as partial gammap and gamm an emission ph components are calculated and compared to experimental data.