Pure rotational spectra of the rare isotopologues of titanium oxide, (TiO)-Ti-46, (TiO)-Ti-47, (TiO)-Ti-49, and (TiO)-Ti-50, have been recorded using a combination of Fourier transform millimeter-wave (FTmmW) and millimeter/submillimeter direct absorption techniques in the frequency range 62-538 GHz. This study is the first complete spectroscopic characterization of these species in their X-3 Delta(r) ground electronic states. The isotopologues were created by the reaction of N2O or O-2 and titanium vapor, produced either by laser ablation or in a Broida-type oven, and observed in the natural Ti isotopic abundances. Between 10 and 11 rotational transitions J + 1 <-> J were measured for each species, typically in all 3 spin-orbit ladders Omega-1,2, and 3. For (TiO)-Ti-47 and (TiO)-Ti-49, hyperfine structure was resolved, originating from the titanium-47 and titanium-49 nuclear spins of I = 5/2 and 7/2, respectively. For the Omega = 1 and 3 components, the hyperfine structure was found to follow a classic Lande pattern, while that for Omega = 2 appeared to be perturbed, likely a result of mixing with the nearby isoconfigurational a(1)Delta state. The spectra were analyzed with a case (a) Hamiltonian, and rotational, spin-orbit, and spin-spin parameters were determined for each species, as well as magnetic hyperfine and electric quadrupole constants for the two molecules with nuclear spins. The most abundant species, (TiO)-Ti-48, has been detected in circumstellar envelopes. These measurements will enable other titanium isotopologues to be studied at millimeter wavelengths, providing Ti isotope ratios that can test models of nucleosynthesis.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/624018 |
| Date | 01 December 2016 |
| Creators | Lincowski, A. P., Halfen, D. T., Ziurys, L. M. |
| Contributors | Univ Arizona, Dept Chem & Biochem, Univ Arizona, Steward Observ |
| Publisher | IOP PUBLISHING LTD |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Article |
| Rights | © 2016. The American Astronomical Society. All rights reserved. |
| Relation | http://stacks.iop.org/0004-637X/833/i=1/a=9?key=crossref.c959a15d32f097cfc411f52baef04879 |
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