Rare gas atomic number dependence of the hyperpolarizability for rare gas inserted fluorohydrides, HRgF (Rg = He, Ar, and Kr).

The three structures of rare gas inserted fluorohydrides HRgF (Rg=He, Ar, and Kr) with all real frequencies are obtained at the QCISD(T)/aug-cc-pVTZ level. The static first hyperpolarizabilities (β0) at the QCISD/aug-cc-pVQZ level are 8 a.u. (HF), 384 a.u. (HHeF), 737 a.u. (HArF), and 465 a.u. (HKrF). The β0 value remarkably increases by about 50–90 times from 8 a.u. (HF) to 384–737 a.u. (HRgF) due to the inserted rare gas (Rg). The Rg atomic number dependence of β0 for HRgF (Rg=He, Ar, and Kr) is found at the first time. The order of β0 is unmonotonic to be HHeF HKrF, but not monotonic (HHeFatomic number dependence of β0 relates to both the geometric effect (expanded H⋯F distance by Rg) and the electronic effect of Rg. From HHeF to HArF and from HArF to HKrF, the preponderant effect on β0 is variational. From HHeF to HArF, the geometric effect is preponderant and the β0 value increases; from HArF to HKrF, the electronic effect of Rg is preponderant and the β0 value decreases...