EXPERIMENTAL DETERMINATION OF THE ELECTRIC DIPOLE MOMENT FUNCTION OF THE $X ^{2}\Pi$ HYDROXYL RADICAL

Abstract

Laboratory infrared emission spectra of $X ^{2}\Pi$ OH obtained with the Solar McMath $FTS^{1}$ and the U. Paris (Orsay) $FTS^{2}$ are used in an inversion procedure to experimentally determine the electric dipole moment function (EDMF) of the hydroxyl radical. The spectra produced at Kitt Peak show vibrational levels up to v = 10 and rotational lines in the range, $-25.5 \leq m \leq 12.5$. The following vibrational quantum number ranges were observed: for $\Delta v = -1, v^{\prime} = 1 - 9$, for $\Delta v = - 2, v^{\prime} = 2 - 10$, and for $\Delta v = -3, v^{\prime} = 6 - 10$. The spectra produced at Orsay show $\Delta v = -1$, with $v^{\prime} = 1 - 4$ and $-22.5 \leq m \leq 9.5$ as well as $\Delta v = 0$, with $v^{\prime} = 1 - 3$, and $9.5 \leq m \leq 25.5$ The OH rovibrational wavefunctions used in the inversion procedure were calculated using a $procedure^{3}$ which reproduces observed rotational constants with a high level of accuracy. Comparisons of our EDMF are made with previous experimental and theoretical work.