We have used continuous-wave cavity ring-down spectroscopy to record a band with origin close to 7275.1 cm(-1) in an Ar supersonic expansion seeded with H2O. It is assigned to nu(1) + nu(3) <- GS, Pi(1(01)) <- Sigma(0(00)) in Ar-H2O. The rotational structure (T-rot =12 K) is analyzed and the lines fitted (sigma = 0.0008 cm(-1)) together with literature microwave data. The fit includes strongly perturbed Q lines, from interaction with a Pi state with origin determined to be close to 7274.5 cm(-1). The mean upper state predissociation lifetime is determined to be 3 ns for all reported e and f upper levels. (C) 2015 Elsevier B.V. All rights reserved.