Ab initio CI calculations on the PE and VUV spectra of hydrogen peroxide

Abstract

Ab initio calculations using a double-zeta basis set including polarization and Rydberg-type orbitals are used to study the first three ionization potentials and the vertical electronic spectrum of H 2O 2 in the spectral region below 10.5 eV. A large-scale CI treatment is found to result in ionization potentials which agree to within less than 0.1 eV with experimental values. The first two transitions (respectively 6.44 and 7.59 eV) in the VUV spectrum are predicted to be of valence-shell type and the corresponding excited states are dissociative. These results agree very well with experimental results on the photolysis of H 2O 2. Between 7.59 and 9.46 eV we find four transitions corresponding to the terms of the first and the second Rydberg series. Beyond 9.46 eV three transitions of intermediate character between valence shell and Rydberg type are predicted.