Line position and line intensity analyses of the high-resolution spectrum of H218O up to the First Triad and [formula omitted

Abstract

Line position and line intensity analyses of the high-resolution spectrum of the H218O isotopic species of the water molecule are performed with the Bending-Rotation approach up to J=17 and the First Triad of interacting states, (020), (100), and (001). The line position analysis involves microwave and terahertz transitions, ground state combination differences, far infrared and infrared lines, and experimental energy levels which were reproduced with a 1.2 unitless standard deviation. The data set considered in the line intensity analysis consists of 3707 infrared transitions recorded using absorption spectroscopy at room temperature which were fitted with a 1.4 unitless standard deviation. The results of both analyses are compared with previous investigations and are used to build a line position and line intensity database to update the HITRAN and GEISA databases. A comparison with the HITRAN 2012 database reveals that the new database yields intensity values closer to the experimental ones.