Bond Dissociation Energy of CO2 with Spectroscopic Accuracy Using State-to-State Resolved Threshold Fragment Yield Spectra.

Abstract

In this study, we present a precise determination of the bond dissociation energy of CO₂ using state-to-state resolved threshold fragment yield spectra at a photoexcitation wavelength of around 92 nm. Our findings show that the bond dissociation energy of CO₂, CO₂ → CO + O, is 43976.12(15) cm^-1 or 526.0714(18) kJ/mol. Furthermore, by incorporating our previously measured bond dissociation energies for CO and O₂, we determined the dissociation energy of CO₂ into C + O₂ and the CO₂ atomization energy (CO₂ → C + O + O) to be 92309.73(21) and 133578.92(18) cm^-1 or 1104.2699(25) and 1597.9592(22) kJ/mol, respectively. Thus, the bond dissociation energies of CO₂ for all channels now have uncertainties of 0.2 cm^-1 or 0.002 kJ/mol. These results serve as reference points for the enthalpies of C atom and CO and CO₂ molecules and provide benchmarks for high-level ab initio quantum chemistry calculations.