- Calculations are carried out on the photoionization of [Formula Presented] molecules in the gas phase, in particular, the photoionization of its highest occupied molecular orbital leading to the formation of [Formula Presented] in the [Formula Presented] state. The computational treatment employs the undistorted orbitals of the neutral molecule and solves the coupled scattering equations for the ejected electron in the field of the molecular ion by using the correct static-exchange interaction within a polyatomic Schwinger variational method with Pad corrections. The total cross section and photoelectron angular distributions show marked resonant features from the threshold up to photon energy of about 30 eV. In the present calculations, all resonances are one-electron resonances of the outgoing electron and are very reminiscent of those predicted for electron-scattering processes from neutral [Formula Presented] The physical implications of this result are analyzed and discussed. 2001 The American Physical Society.