Journal of Electron Spectroscopy and Related Phenomena, 21 (1980) 171-174 0 Elsevler Sclentlflc Pubhshmg Company, Amsterdam - Printed m The Netherlands Short commumcatlon RELATIVE INTENSITIES IN THE He(I) AND He(I1) PHOTOELECTRON SPECTRA OF BENZOYL CHLORIDE M M GOFMAN, V G YARZHEMSKY and V I NEFEDOV N S Kurnakov Insfrtute of General and Inorganrc Chemistry, US S R Academy of Sczences, Moscow (U S S R ) (Received 20 May 1980) In previous work [ 1] photolomzatlon cross-sections for the first-row atomic orbltals were calculated using the RPAE method The molecular- orbital cross-sections for some small molecules were obtamed on the basis of the Gehus-Slegbahn formula, and the results were quite reliable up to low photon-energies It 1s of mterest to check the valldlty of our approach for relatwely large molecules In this commumcatlon we present the calculated Cl 3s and Cl 3p photolomzatlon cross-sections as well as their relative mten- sltles in the He(I) and He(H) photoelectron spectra of benzoyl chlonde (CgH5 COCl) The cross-sections and asymmetry parameters for the Cl 3s and Cl 3p photolonlzatlons were calculated by the RPAE method using the computer program [ 21 for the average of conflguratlons of the Cl atom (see ref 1 for detds) In this method the correlations within each of the transltlons 3p + Ed, 3p + es, 3s + ep and between V~XXOUS transltlons are taken mto ac- count The results for photon energes from the threshold up to 160 eV are presented m Fig 1 The photolonlzatlon cross-sections for the 3p5 shell of chlorme have been calculated mthm the framework of the RPAE method by Starace and Armstrong [3] and also by Cherepkov and Chernysheva [ 41 whose results are also presented m Fig. 1 It can be seen that our average-of- conflguratlons approach [l] leads to cross-sectlons which are very close to the results of exact RPAE calculations for the open shell [ 41 Recently, Gan et al [5] have measured the He(I) and He(I1) photoelec- tron spectra of benzoyl chlonde and analyzed the relative band-mtensltles for these spectra. Their interpretation was based on ab mltlo calculations on CgH5 COCl carned out with a mmlmal basis STO-3G. Using the results of this calculation we have determined the atomic populations of the molecular