Barrier Height for the Exchange Reaction F + HF → FH + F

Barrier Height for the Exchange Reaction F + HF → FH + F

Department of Chemistry and Lawrence Berkeley Laboratory, University of California, Berkeley, Calif. 94720
^*Lawrence Livermore Laboratory, University of California, Livermore, Calif. 94550

Abstract

There exists a body of conflicting data as to the existence or nonexistence of FHF, ClHCl, BrHBr, and IHI as chemically bound molecular species. Ab initio quantum mechanical electronic structure calculations are presented which predict linear symmetric FHF to be unstable. The barrier height for the F + HF exchange reaction is suggested to be no less than 18 kcal/mol, much larger than expected either intuitively or on the basis of certain experiments on related systems. The expected reliability of the calculations is based upon comparable results for diatomic molecules and the F + H₂ and H + F₂ potential energy surfaces.