ANGLE-RESOLVED PHOTOELECTRON SPECTROMETRY OF ATOMIC CHLORINE USING SYNCHROTRON RADIATION

Using synchrotron-radiation-based angle-resolved photoelectron spectrometry, the Cl 3s3p5(P-3(2)o,1,0)np and 3s3p5(P-1(1)o)np autoionizing Rydberg series are studied by monitoring the relative partial photoionization cross sections and asymmetry parameters of the 3p-1 P-3(2,1,0)e, D-1(2)e, and S-1(0)e ionic states between 21.75 and 27.75 eV. The Rydberg series converging upon the 3s-1 P-3(2)o, P-3(1)o, and P-3(0)o, thresholds are clearly resolved. Rydberg levels up to n = 14 can be identified in the (P-3(2,1,0)o)np series, while the (P-1(1)o)np Rydberg series can be observed up to n = 10. The relative partial cross sections are placed on an absolute scale using previous data obtained with an electron spectroscopy modulation method. The present experimental results for the Cl (P-3(2,1,0)o)np and (P-1(1)o)np Rydberg series are compared with those of the Ar 3s3p6(S-2(1/2)e)np series, and with theoretical results of a nonrelativistic many-body perturbation theory calculation. The P-3(2,1,0)o and P-1(1)o ionization thresholds obtained from the Rydberg series agree very well with the ionization limits calculated on the basis of the Cl II spectrum, and with the ionization energies determined from a 3s-1 photoelectron spectrum. Autoionization phenomena due to 3s(2)3p5-->3s(2)3p3nln'l' two-electron excitations are observed in the P-1(1)o resonance region.