Online version of ezSpectrum computes stick photoelectron/photodetachment spectra for polyatomic molecules within the double-harmonic parallel-mode approximation, i.e., the Franck-Condon factors (FCF) are calculated as overlaps of one-dimensional harmonic wave functions assuming that their ionization results only in normal mode displacements and frequency changes, neglecting mode mixing (Duschinsky rotations are available in the offline version). For more information, the manual, and to download the full compiled Linux version of ezSpectrum please see iOpenShell/Downlads

The calculation of the spectrum requires equilibrium geometries, harmonic frequencies, and normal mode vectors for the initial and the target electronic states, which can be computed by ab initio packages. Using the link below you can upload outputs with frequency jobs computed with Q-Chem, ACES, Molpro, GAMESS, or Gaussian packages (a separate output for each electronic state); ezSpectrum will extract the required data from your outputs.

Or start by trying one of the prepared examples:

Photoelectron spectrum of trans-HCOH
Photoelectron spectrum of the oxyallyl anion radical (CH2COCH2)&ndash

Your comments or suggestions are very welcome. Please post your ideas at the iOpenShell forum, or contact us at: Vadim Mozhayskiy and Anna Krylov