HIGH-TEMPERATURE SPECTRUM OF H2O IN THE 720-1400 CM(-1) REGION

Spectral line positions and line position uncertainties have been dete rmined for 1605 absorption lines of H2O in the spectral region from 72 0 to 1400 cm(-1). Of these, transition identifications were confirmed for 921 of the spectral lines. The line-position measurements were obt ained from a transmittance spectrum having a signal-to-noise ratio gre ater than 100 to 1. The apodized spectral resolution was 0.009 cm(-1). The 20 Torr H2O sample was heated to approximately 1000 K, in a 1.75 m single pass sample cell. The wavelength scale pf the transmittance s pectrum was calibrated by using strong well-known H2O spectral lines. The line-position estimates and identifications were checked using a m odified Loomis-Wood diagram technique. Initial guess line-position est imates were obtained from either HITRAN92 or a direct numerical diagon alization (DND) calculation of the H2O Hamiltonian. The transition ide ntifications were confirmed and a consistent set of line-position valu es determined using a combination-difference technique to check closed loops on an energy level diagram. A few large (> 0.1 cm(-1)), and man y smaller (from 0.1 to 0.001 cm(-1)), line position differences were f ound when the measured line positions were compared to the values on H ITRAN92. These differences are all larger than the line-position measu rement uncertainties, which are generally less than 0.001 cm(-1). Many of the new and confirmed H2O line-position measurements have been inc orporated into HITRAN96. Published by Elsevier Science Ltd.