Knowledge Bank

Predissociation line widths of the $(3,0)-(11,0)$ Schumann-Runge bands of $\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}O2$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">16</mrow>}O18O$ in the wavelength region 180-196 am have been obtained from the published measurements of the absolute absorption cross sections of Yoshino $etal.1,2$ and spectroscopic constants of these molecules of $Cheung3,4$. The line widths are determined as parameters in the non-linear least squares fitting of calculated to measured cross sections. Predissociation maxima are found at upper vibrational levels with $v\prime =4,7$ and 10 for $\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}O2$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}O18O$. Our predissociation line widths are mostly greater than previous experimental values for both isotopic molecules. This work is supported by NASA grant NAG 5-484 to Smithsonian Astrophysical Observatory