We have studied the photoionization cross sections and photoelectron asymmetry parameters for all molecular orbitals of acetylene. These cross sections were obtained using accurate frozen-core Hartree–Fock continuum orbitals in the final-state wave function. The Hartree–Fock continuum equations were solved using the iterative Schwinger variational method. These fixed-nuclei cross sections are compared with available experimental data and with results obtained using the Stieltjes moment theory approach and the continuum multiple scattering method. The possible role of a shape resonance in the 1piu-->kpig channel and the resonant structure of the sigmau continuum are discussed in some detail
