IDENTIFICATION OF THE CORE-HOLE EXCITED-STATES OF N-2 - A FAILURE OF THE EQUIVALENT CARE APPROXIMATION

Monochromatic soft x-rays were used to excite the nitrogen molecule at resonances near the K-ionization edge. The absorption anisotropy para meter beta was determined from the simultaneous measurement of the pho tofragment flux emanating from the x-ray/molecular-beam interaction re gion along two axes, one parallel and the other perpendicular to the e lectric vector of the polarized synchrotron radiation. The value of th e anisotropy parameter identifies the symmetry species of a resonance and allows the core-hole excited states to be assigned from experiment al data. These data force a new assignment of Rydberg states and revea l a failure of the equivalent core approximation.