The pure rotational spectrum of TiS (X3Δr) at submillimeter wavelengths

0022-2852/$ see front matter 2010 Elsevier Inc. A doi:10.1016/j.jms.2010.09.005 ⇑ Corresponding author at: Department of Chem University of Arizona, 933 N. Cherry Ave., Tucson, AZ 5554. E-mail address: [email protected] (L.M. Ziury 1 Present address: National Radio Astronomy Obs Charlottesville, VA 22903, USA. The pure rotational spectrum of TiS in its XDr ground state has been measured using millimeter–wave direct-absorption techniques in the frequency range of 313–425 GHz. This free radical was created by the reaction of titanium vapor, produced in a high-temperature Broida-type oven, with H2S. Eight to ten rotational transitions were recorded for the main titanium isotopologue, TiS, in the v = 0 and v = 1 levels, as well as for the v = 0 state of TiS, observed in natural abundance (Ti:Ti = 74:8). All three X components were observed in almost every recorded transition, with no evidence for lambda-doubling. The data were fit with a Hund’s case(a) Hamiltonian, and rotational, spin–orbit, and spin–spin constants were determined, as well as equilibrium parameters for TiS. Relatively few fine structure parameters were needed for the analysis of TiS (A, AD, and k), unlike other 3d metal species. The rotational pattern of the three fine structure components suggests the presence of a nearby excited D state, lying 3000 cm 1 higher in energy. From the equilibrium parameters, the dissociation energy for TiS was estimated to be 5.1 eV, in reasonable agreement with past thermochemical data. 2010 Elsevier Inc. All rights reserved.