Supersonic Jet Spectroscopy on TiO 2 Millimeter-wave Spectroscopy of Titanium Monoxide and Titanium Dioxide 63 rd International Symposium on Molecular Spectroscopy, Ohio June 19, 2008 PATRIK KANIA, THOMAS F. GIESEN, HOLGER S. P. MÜLLER, STEPHAN SCHLEMMER I. Physikalisches Institut, Universität zu Köln SANDRA BRÜNKEN Harvard-Smithsonian Center for Astrophysics, Cambridge

TiO abundant in M & S stars; absorption used for classification TiO 2 important ingredient of O-rich grains transition metal compounds important as catalysts TiO 2 common substrate for surface science Ti abundant transition metal; Ti/H ≈ 3 × 10 −8 Astrophysical Interest small molecules with transition metals of fundamental interest Quantum Chemical Interest

63 rd International Symposium on Molecular Spectroscopy, Ohio June 19, 2008 Optical : A – X band system study, R. S. Ram, P. F. Bernath, M. Dulick, and L.Wallace, ApJS, 122, 331 (1999) Infrared: No rotationally resolved data available Millimeter wave: 220 – 460 GHz 48 TiO main isotope K. Namiki, S. Saito, J.S. Robinson, and T.C. Steimle, J. Mol. Spectrosc. 191, (1998) Titanium monoxide TiO 3  Electronic Ground State Isotopes of Titanium 46 Ti: 8.25 % 47 Ti: 7.44 % (I = 5/2) 48 Ti: % 49 Ti: 5.41 % (I = 7/2) 50 Ti: 5.18 %

New Measurements 46 TiO, 50 TiO First pure rotational transitions Extended measurements on 48 TiO Data for the 3  1 3  2 states Titanium monoxide TiO 3  Electronic Ground State Isotopes of Titanium 46 Ti: 8.25 % 47 Ti: 7.44 % (I = 5/2) 48 Ti: % 49 Ti: 5.41 % (I = 7/2) 50 Ti: 5.18 % 63 rd International Symposium on Molecular Spectroscopy, Ohio June 19, 2008

PLL beam splitter Rb-reference BWO-supply BWO harmonic mixer He pulse generator valve l-He digital lock-InPCsynthesizer pump 250 – 350 GHz Nd:YaG laser 63 rd International Symposium on Molecular Spectroscopy, Ohio June 19, 2008 Cologne Supersonic Jet Spectrometer for Terahertz Applications (SuJeSTA)

Pulsed Laser Laser Ablation Source for TiO and TiO 2 backing pressure2 – 2,5 bar chamber pressure5·10  5 bar buffer gasHe laser energy per pulse mJ width of laser pulse6 ns repetition rate30 Hz Multipass 10 passes path length 30 cm Pulsed Nozzle rotating Ti rod for TiO + 1 % O 2 for TiO % O 2 63 rd International Symposium on Molecular Spectroscopy, Ohio June 19, 2008 Nd:YaG 1064 nm TiO 2

J : 10 ← 9 63 rd International Symposium on Molecular Spectroscopy, Ohio June 19, 2008 Spectra of 48 TiO and 46 TiO in natural abundance Frequency [GHz] Intensity [a.u.] 48 TiO 73,8 % 46 TiO 8,0 %

Data analysis using SPFIT/SPCAT including data from Namiki et al. (1998) Analysis of TiO Parameters are given in MHz. Standard deviations of all parameters given in parentheses are in units of the corresponding last digits. a, b Fixed to the value of R. S. Ram, P. F. Bernath, M. Dulick, and L.Wallace, ApJS, 122, 331 (1999) 63 rd International Symposium on Molecular Spectroscopy, Ohio June 19, 2008

Asymmetry:  = Spin statistics: K a + K c even allowed Spectrum: b-type 63 rd International Symposium on Molecular Spectroscopy, Ohio June 19, 2008 TiO 2 dipole moment: 6.7D Energy Level Diagram of TiO 2 S. Brünken, H. S. P. Müller, K. M. Menten, M. C. McCarthy, and P. Thaddeus, ApJ 676, 1367 (2008) Titanium dioxide ( 1 A 1 )

First pure rotational studies of TiO 2 S. Brünken, H. S. P. Müller, K. M. Menten, M. C. McCarthy, and P. Thaddeus, ApJ 676, 1367 (2008) 27 observed transitions in the 7 – 42 GHz range for three isotopomers 46 TiO 2, 48 TiO 2, 50 TiO 2 63 rd International Symposium on Molecular Spectroscopy, Ohio June 19, 2008 Intensity / nm 2 MHz Frequency [GHz] TiO 2 rotational spectrum at 10 K

Energy Level Diagram of TiO 2

J Ka,Kc : 8 5,3 ← 7 4,4 J Ka,Kc : 9 5,5 ← 8 4,4 63 rd International Symposium on Molecular Spectroscopy, Ohio June 19, 2008 Example of the 48 TiO 2 measured spectra

46 TiO 2 - 8,0 % 47 TiO 2 - 7,3 % 48 TiO ,8 % 49 TiO 2 - 5,5 % 50 TiO 2 - 5,4 % J Ka,Kc : 7 5,3 ← 6 4,2 Stable isotopomers of titanium dioxide 63 rd International Symposium on Molecular Spectroscopy, Ohio June 19, 2008

Data fitted to A-reduced Watson Hamiltonian including data from (Brünken et al. 2008) Analysis of TiO 2 Parameters are given in MHz. Standard deviations of all parameters given in parentheses are in units of the corresponding last digits Isotopics ratios kept fixed for distortion parameters

TiO First pure rotational transitions of 46 TiO and 50 TiO Isotopic invariant fit in progress TiO 2 Extended measurements up to J = 22, K a = 8 (T= 150 K) Higher order centrifugal parameters Data for astronomical observations Conclusion