Water-Vapor Absorption Database using Dual Comb Spectroscopy from 300-1300 K Part II: 2% H2O in Air, 6600 to 7650 cm-1

We present broadband dual frequency comb laser absorption measurements of 2% H2O (natural isotopic abundance of 99.7% H216O) in air from 6600-7650 cm-1 (1307-1515 nm) with a spectral point spacing of 0.0068 cm−1. Twenty-nine datasets were collected at temperatures between 300 and 1300 K (±0.82% average uncertainty) and pressures ranging from 20 to 600 Torr (±0.25%) with an average residual absorbance noise of 8.0E-4 across the spectrum for all measurements. We fit measurements using a quadratic speed-dependent Voigt profile to determine 7088 absorption parameters for 3366 individual transitions found in HITRAN2020, building on the line strength, line center, self-broadening, and self-shift parameters determined in the Part I companion of this work. Here we measure air-width (with temperature- and speed-dependence) and air-shift (with temperature-dependence) parameters. Various trends are explored for extrapolation to any weak transitions that were not covered in this work. Improvements made in this work are predominantly due to the inclusion of air-shift temperature dependence values. In aggregate, these updates improved RMS absorbance error by a factor of 4.2 on average, and the remaining residual is predominantly spectral noise. This updated database improves high-temperature spectroscopic knowledge across the 6600-7650 cm-1 region of H2O absorption.