A new analysis of the \nu_2 fundamental band of H₂O⁺

This paper reports that the absorption spectra of H₂O⁺ have been measured by tunable mid-infrared diode laser spectroscopy in the spectral range of 1100--1380cm^-1. The H₂O⁺ ions are generated in an AC glow discharge of the gaseous mixtures of H₂O/He and detected with the velocity modulation technique. Forty new lines are assigned to the \nu_2 fundamental band of H₂O⁺ (\tildeX^2B_1). The observed lines together with other data published previously are fitted to the standard effective Hamiltonian of an asymmetric top, yielding a set of improved rotational constants, spin-rotation constants and their quartic and sextic centrifugal distortion constants for the \nu_2=1 vibrational state of H₂O⁺.