Matrix-isolation and ab initio study of HNgCCF and HCCNgF molecules (Ng = Ar, Kr, and Xe)

We report three new noble-gas molecules prepared in low-temperature Kr and Xe matrices from the HCCF precursor by UV photolysis and thermal annealing. The identified molecules are two noble-gas hydrides HNgCCF (Ng = Kr and Xe) and a molecule of another type, HCCKrF. These molecules are assigned with the help of ab initio calculations. All strong absorptions predicted by theory are found in experiments with proper deuteration shifts. The experiments and theory suggest a higher stability against dissociation of HNgCCF molecules compared to HNgCCH reported previously. Surprisingly, only very tentative traces of HCCXeF, which is computationally very stable, are found in experiments. No strong evidence of similar argon compounds is found here.