The mysterious near-UV absorber in the Venusian atmosphere

Abstract or Summary

The absorption spectrum of two recently identified molecules in the atmosphere of Venus were simulated. The electronic absorption spectra of some small sulfur-containing molecules of atmospheric importance namely, sulfur dioxide (SO2), sulfur trioxide (SO3), hydrogen sulfide (H2S), carbonyl sulfide (OCS), and carbon disulfide (CS2), have been simulated using a nuclear ensemble approach with the Newton-X1 package. The ensemble is based on Wigner sampling of vibrational frequencies calculated at the CCSD(T) level of theory with the aug-cc-pV(T+d)Z basis set. The electronic excited state transition energies and oscillator strengths of each geometry in the ensemble are calculated with the EOM-CCSD, using correlation consistent basis sets with additional diffuse basis functions, denoted augcc-pV(X+d)Z+3. We find very good agreement between our calculated spectra and the available experimental spectra. We apply the combination of theoretical parameters that was considered suitable for calculating the electronic absorption spectrum of the benchmarking molecules on two sulfur-containing molecules without previous experimental spectra, sulfuric acid (H2SO4) present in Earth’s atmosphere2 and OSSO recently identified in atmosphere of Venus3 and simulate their ab initio, the electronic absorption spectrum under atmospherically relevant conditions.