An ab initio study of the mono- and difluorides of krypton

Results from ab initio calculations at the CCSD(T) level of theory are pres ented for krypton monofluoride (KrF), krypton monofluoride cation (KrF+), l inear, ground-state krypton difluoride (KrF2), the triplet state of krypton difluoride, and the krypton-fluorine van der Waals complex (Kr-F-2). These are the first calculations demonstrating that KrF is a bound molecule, in agreement with experimental observation. When corrected for basis-set super position error, the calculated potential displays quantitative agreement wi th the attractive wall of the experimentally measured potential curve. Resu lts are also presented for KrF+ and linear KrF2 which yield accurate values for their dissociation energies, The tripler state of KrF2 is found to hav e a minimum energy below that of separated atoms, and its structure is bent , with a small F-Kr-F bond angle (71 deg). The van der Waals complex, Kr-F- 2, appears to consist of an unperturbed F-2 molecule attached to a krypton atom in the expected T-shaped structure. (C) 1998 American Institute of Phy sics. [S0021-9606(98)30448-1].