ROTATIONAL AND VIBRATIONAL EFFECTS IN PHOTOIONIZATION - BRIDGING THE GAP FROM MICROVOLTS TO KILOVOLTS

We present measurements on photoion rotational and vibrational branchi ng ratios following 2 sigma(u)(-1) photoionization of N-2 and 4 sigma( -1) photoionization of CO. The strategy employed in these studies, det ecting dispersed fluorescence from electronically excited photoions, e xtends the accessible range by orders of magnitude as even the rotatio nally resolved data have been obtained at electron kinetic energies ex ceeding 230 eV. We find that both shape resonances and Cooper minima e xert dramatic influence on the photoion internal degrees of freedom, e ven at the highest measurable energies.