Shape resonances in angle-resolved photoionization of aligned CF3I molecules

The photoionization of CF3I molecules in the photon energy range between 10 eV and 40 eV is investigated using angle-resolved photoelectron spectroscopy in the molecular frame. Using a femtosecond laser pulse, the molecules are impulsively aligned prior to their ionization by a series of extreme ultra-violet photon energies obtained by high-harmonic generation. The manifestation of molecular alignment in the photoelectron angular distributions (PADs) is well reproduced by non-relativistic quantum-mechanical photoionization calculations carried out with the ePolyScat software package, taking into account all open ionization channels. Our analysis points to two prominent shape resonances that dominate the photoelectron scattering dynamics and that therefore largely explain the observed changes in the PADs as a function of molecular alignment.

Automated summary

We investigate the photoionization of CF3I molecules in the energy range of 10 eV to 40 eV using angle-resolved photoelectron spectroscopy in the molecular frame. By using a femtosecond laser pulse, the molecules are aligned before ionization with extreme ultraviolet photon energies generated by high-harmonic generation. Non-relativistic quantum-mechanical photoionization calculations with the ePolyScat software package, considering all open ionization channels, reproduce well the manifestation of molecular alignment in photoelectron angular distributions (PADs). Our analysis reveals two dominant shape resonances that largely explain the observed changes in the PADs as a function of molecular alignment.