Analysis of a remarkable perpendicular band in KrH2O with origin close to the ν1 + ν3 R(0) line in H2O

We have used continuous-wave cavity ring-down spectroscopy to record a band with origin close to 7273.5 cm−1 in a Kr supersonic expansion seeded with H2O. It is assigned to ν1 + ν3 ← GS, ∏(101) ← Σ(000) in KrH2O. Several lines of the four most abundant Kr isotopic forms are resolved. The rotational structure (Trot = 18 K) is analyzed and the lines fitted (σ < 0.0004 cm−1) together with literature microwave data. The mean upper state predissociation lifetime is estimated to 4 ns.