Further study of exchange-correlation functionals for the calculations of outer-valence ionization potentials of gas-phase molecules

Earlier study of exchange-correlation functionals for the calculations of outer-valence ionization potentials of 31 molecules shows that our Density Functional Theory (DFT) method called ∆PBE0(SAOP) performs very well except for the three perhalogenated molecules included in the study. The present work expands the study to 85 molecules including 40 containing halogens. Analysis of a total of 500 vertical ionization potentials (VIPs) confirms that ∆PBE0(SAOP) continues to excel for nonhalogenated molecules with an average absolute deviations (AAD) of 0.19 eV and reveals that the best method for halogenated molecules is ∆mPW1K(SAOP) with an AAD of 0.21 eV.