Probing the unusual isotope effects in ozone formation: Bath gas and pressure dependence of the non-mass-dependent isotope enrichments in ozone

► Bath gas and pressure dependence of heavy isotope enrichments in O3 were measured. ► All isotope selectivity is eliminated for O3 formed in an SF6 bath by 700 Torr. ► Results provide new insights into the non-mass-dependent isotope effects in ozone formation and new benchmarks for theory.