Isotopic Spectra of the Hydroxyl Radical

Rotational spectra of OH and its isotopologues have been precisely measured using high efficiency terahertz (THz) sources. The measurements are compared with existing data and are useful for global modeling. For the first time, microwave measurements of the Λ-doubling transitions of the 17OH isotopologue are combined with THz data successfully. Precise rotational, fine-structure, and hyperfine structure parameters for the 17OH isotopologue are reported. An isotopically independent Dunham model for all isotopologues of 2Π OH v < 3 is presented.