3P-PHOTOIONIZATION RESONANCES OF ATOMIC FE, CO, AND NI STUDIED BY THEOBSERVATION OF SINGLY AND DOUBLY-CHARGED PHOTOIONS

Using monochromatized synchrotron radiation and atomic beam technique the photoion spectra of Fe, Co, and Ni in the region of the 3p resonan ces were measured. For the interpretation of the spectra the photoioni zation cross sections were calculated, taking into account strong inte rconfiguration mixing of the type (3d,4s)(N) and the thermal populatio n of the different fine-structure levels in the ground states accordin g to the temperature of about 1800 K for the evaporation of the metals . The calculations were performed in the framework of overlapping reso nances interacting with many continua. Good agreement of the main feat ures with the experimental results were obtained. Special emphasis is given to the discussion on the origin of doubly charged photoions.