Accurate frequency measurements for H2O and O-16(3) in the 119-cm(-1) OH atmospheric window

We report frequency measurements for relatively weak H2O and O-16(3) rotational transitions in the ground state and in the v(2) = 1 vibrationally excited state. We obtained the frequency measurements by using the laboratory technique of tunable far-infrared spectroscopy with the objective of improving H2O and O-3 line parameters required for modeling the important atmospheric spectral window near 119 cm(-1). New sets of molecular constants are calculated from the O-16(3) data, and improved values are reported for the frequencies of the H2O lines. The improvement in atmospheric simulations obtained with the new results is illustrated by comparison with recent high-resolution balloon-based atmospheric measurements. These new data significantly improve simulations of high-resolution atmospheric emission spectra. (C) 1997 Optical Society of America.