K-shell photoionization of CO: I. Angular distributions of photoelectrons from fixed-in-space molecules

Angular distributions of photoelectrons from both C and O K-shells of the f ixed-in-space CO molecule have been measured using the angle-resolved photo eletron-photoion coincidence technique. The measurements have been performe d at several photon energies from the ionization thresholds up to about 30 eV above them, where the sigma* shape resonances occur. Experimental result s are compared with the multiple-scattering calculations of Diil et al (197 6 J. Chem. Phys. 65 3158) and with our new calculations in the relaxed-core Hartree-Fock approximation. Our calculations are in a better agreement wit h the experimental data though numerical discrepancies remain. The experime ntal angular distributions are fitted by the expansion in Legendre polynomi als containing up to ten terms and the extracted parameters are compared wi th the corresponding theoretical values.