Fluoro Hydrogen Peroxide and Other Substituted Peroxides as Sinks for the Elusive Fluorine and Sulfur Atoms

Fluorine’s hostile nucleosynthetic environment makes it one of the least common elements and, consequently, understudied both on the earth and in the interstellar medium (ISM). However, the presence of fluorine-containing species in both the ISM and in the earth’s atmosphere necessitates the existence of a pathway out of this environment to form fluorine-containing molecules. To that end, the presence of fluorine and hydroperoxyl radical (HO₂) in either of these environments may lead to the formation of fluorinated molecules like fluoro hydrogen peroxide (HOOF) on dust grains of protoplanetary disks in the planet-forming regions of ρ Oph and in the earth’s atmosphere as a sink for other fluorine pollutants that have yet to be detected. This theoretical study utilizes explicitly correlated coupled cluster theory computed with core correlation and corrections from scalar relativity to provide the first anharmonic fundamental vibrational frequencies and rotational constants of HOOF, and other similarly substituted hydrogen peroxide species, for use as reference benchmarking of further computational or experimental study, as well as potential astrophysical and atmospheric observation. The ν₆ bending frequency for HOOF at 454.4 cm^–1 exhibits an anharmonic transition intensity of 78 km/mol, while the ν₄ frequency at 738.2 cm^–1 is 66 km/mol. Additionally, HOOF has a large net dipole moment of 2.12 D compared to the previously detected HF and HOOH molecules, 1.82 and 1.85 D, respectively, resulting from the electronegativity of the fluorine. Consequently, HOOF is a likely candidate for possible detection via vibrational and rotational spectroscopy to further the understanding of fluorine’s small, but important, role in astrochemical and atmospheric environments.