Active Thermochemical Tables: The Adiabatic Ionization Energy of Hydrogen Peroxide

Abstract

The adiabatic ionization energy of hydrogen peroxide (HOOH) is investigated, both by means of theoretical calculations and theoretically assisted reanalysis of previous experimental data. Values obtained by three different approaches: 10.638 ± 0.012 eV (purely theoretical determination), 10.649 ± 0.005 eV (reanalysis of photoelectron spectrum), and 10.645 ± 0.010 eV (reanalysis of photoionization spectrum) are in excellent mutual agreement. Further refinement of the latter two values to account for asymmetry of the rotational profile of the photoionization origin band leads to a reduction of 0.007 ± 0.006 eV, which tends to bring them into even closer alignment with the purely theoretical value. Detailed analysis of this fundamental quantity by the Active Thermochemical Tables approach, using the present results and extant literature, gives a final estimate of 10.641 ± 0.006 eV.

Th2O–, Th2Au–, and Th2AuO1,2– Anions: Photoelectron Spectroscopic and Computational Characterization of Energetics and Bonding

“…The lowest energy structures all involve the O atom interacting with Th because the interaction of O with Au would involve a very high-energy species. This is consistent with the high bond energy for ThO at 208.5 kcal/mol and the much lower BDE (bond dissociation energy) for AuO at 53.5 ± 5 kcal/mol . The lowest energy structure for the anion is the singlet C 2 v structure with the O atom bridging the Th–Th bond and with the Au atom bridging Th–Th bond opposite to the O atom.…”

“…BDEs are valuable parameters for understanding the bonding in these species. The BDE of AuO has been reported to be 53.3 ± 5 kcal/mol, whereas our calculated value of 48 kcal/mol is slightly smaller than that, it is likely to be more reliable . Roos et al .…”

“…Heats of formation at 0 K were calculated by combining our computed Σ D 0 values with the known enthalpies of formation at 0 K for the elements with Δ H f,0K (O) = 59.00 ± 0.00 kcal/mol, from the active thermochemical tables (ATcT), − Δ H f,0K (Au) = 88.0 ± 0.5 kcal/mol, and Δ H f,0K (Th) = 143.9 ± 1.4 kcal/mol . Note that there is another value reported for Δ H f,0K (Th) = 142.1 ± 1.5 kcal/mol .…”

CheKiPEUQ Intro 1: Bayesian Parameter Estimation Considering Uncertainty or Error from both Experiments and Theory**

“…This allows the growing databases of values and theoretical predictions to be better connected to experiments for the extraction of physically relevant parameters. The BPE approach has already been applied to gas phase molecular thermodynamics for reaction energies [28–30] …”

The adiabatic ionisation energy of CO2

“…Precise measurements of ionization energies are also used as benchmarks for comparison with the results of first-principles quantum-chemical calculations (see, e.g., Refs. [4][5][6]). Rydberg-series extrapolation and high-resolution photoelectron spectroscopy are currently the methods of choice to determine ionization energies of neutral molecules and typically allow accuracies in the range 0.1 − 1 meV (i.e., about 1 − 10 cm −1 ) in polyatomic molecules [7].…”