Survey of main group compounds (HBr) at the Gaussian-4 level of theory: Adiabatic ionization energies and enthalpies of formation

Gas phase adiabatic ionization energies (AIEs) and standard state (298.15 K, 1 atm) enthalpies of formation Δ f H ( g ) ° were calculated at the Gaussian-4 (G4) level of theory for a suite of 319 and 398 main group compounds, respectively, containing the elements hydrogen through bromine. National Institute of Standards and Technology (NIST) evaluated AIEs were available for comparison with 44 compounds, yielding good agreement when the significant variability among the individual experimental reports was taken into consideration. AIEs were estimated at the G4 level of theory for a further 126 main group compounds having at least one experimental datapoint in the NIST database, but not a NIST evaluated AIE, as well as 149 main group compounds without any experimental data in the NIST database. Experimental Δ f H ( g ) ° were available for comparison with 144 compounds, yielding good agreement, particularly against compounds with evaluated Δ f H ( g ) ° . Δ f H ( g ) ° were estimated at the G4 level of theory for a further 254 main group compounds without any experimental data. The datasets comprise a benchmark set of theoretical data against which to assess future experimental and theoretical results.