Knowledge Bank

Accurate line parameters for the near-infrared electronic bands of $O2$ are important for atmospheric modeling and remote sensing. Here, we report measurements of the rotional linestrengths and pressure-broadening coefficients for the $v=0\leftarrow 0$ component of the a $a\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Delta g\leftarrow X\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma g+$ band of $O2$ near $7882cm-1$. The measurements have been measured at $0.01cm-1$ resolution and sample pressures from 13kPa to 101kPa using a Fourier-transform infrared spectrometer and a White cell with an optical pathlength of 84 m. The rotational lines follow magnetic-dipole selection rules and have intensities proportional to the sample pressure. The resolved rotational structure overlaps the electric-dipole-allowed collision-induced continuum absorption which is due to binary $O2$ collisions and which dominates at higher sample pressures. The present measurements will be compared to recent results by other investigators. Efforts are presently underway to determine continuum parameters for the collision-induced background absorption.