Photoelectron angular distributions of H2O

The partial cross section and asymmetry parameters of the 2B1, 2A1, and 2B2 ionic states of H2O+ have been measured at photon energies of 18–31 eV, by time-of-flight photoelectron spectroscopy using synchrotron radiation. The atomic character of the molecular orbitals is discussed in the interpretation of similarities and differences between the measurements for these states. Other synchrotron radiation data, resonance line measurements, and (e, 2e) dipole results are included. A multiple-scattering Xα (MSXα) calculation and a ground-state inversion method calculation are in good agreement with our cross section measurements. There is excellent agreement between experimental asymmetry parameters and those computed from the MSXα method. Stieltjes–Tchebycheff imaging model calculations suggest the presence of resonant channels. This may be the origin of weak resonance structure present in the measurements.