Oscillatory structure of molecular photoionization cross sections

Oscillatory structure in electron angular distributions, due to interferenc e between electron waves scattered from different centers, is a central the me in the use of photoionization to explore extended structures (molecules, solids, surfaces, etc.). The very simplest case, photoionization of H-2(+) , was analyzed long ago by Cohen and Fano [Phys. Rw. 150, 30 (1966)]. Here we extend their analysis and show that similar effects are to be expected i n the relatively new field of photo double ionization of small molecules.