June 22-26, th International Symposium on Molecular Spectroscopy The Pure Rotational Spectrum of CrS (X 5  r ): Continued Studies of the 3d Transition Metal Sulfides Robin L. Pulliam, Amanda J. Higgins, and Lucy M. Ziurys University of Arizona, Department of Chemistry, Department of Astronomy, Steward Observatory, Arizona Radio Observatory, Tucson, AZ

June 22-26, th International Symposium on Molecular Spectroscopy An Introduction Previous transition metal sulfide work – VS : Laser Spectroscopy; ScS: Molecular beam optical stark measurements – MnS, FeS, NiS: previous microwave and mm-wave studies – CoS, CuS, CrS (this talk), TiS( FC11), ZnS ( FC02) – Ziurys Lab Material Sciences – metal sulfides are to known penetrate metals and alter structures and mechanical properties of metal – Solid lubricants Astrochemistry – Chromium is considered a relatively abundant nucleus – Cr atomic lines observed around stars – CrH observed around brown dwarf stars and possibly sunspots ScSTiSVSCrSMnSFeSCoSNiSCuSZnS 2+2+33 4-4-55 6+6+55 44 3-3-22 1+1+

June 22-26, th International Symposium on Molecular Spectroscopy Laser-Induced Fluorescence Spectroscopy of CrS 5832 MHz 4 MHz

June 22-26, th International Symposium on Molecular Spectroscopy Submillimeter Spectroscopy Radiation Source: Phase- locked Gunn oscillators and Schottky diode multipliers ( GHz) Gaussian beam optics utilized to minimize radiation loss Reaction Chamber: Double walled, steel cell which contains a Broida-type oven Detector: InSb bolometer Radiation is modulated at 25kHz and detected at 2f

June 22-26, th International Symposium on Molecular Spectroscopy Molecular Synthesis Sublimed chromium metal in Broida type oven (m.p °C ) – Chromium pieces (99.2% Alfa- Aesar) – Tungsten wire baskets – Alumina crucibles – Molybdenum post – Insulated with alumina crucible pieces and ZrO felt Hydrogen sulfide gas – Between 3-5 mtorr for best production Production unstable at times

June 22-26, th International Symposium on Molecular Spectroscopy

June 22-26, th International Symposium on Molecular Spectroscopy

June 22-26, th International Symposium on Molecular Spectroscopy

June 22-26, th International Symposium on Molecular Spectroscopy Data & Analysis

June 22-26, th International Symposium on Molecular Spectroscopy J+1←JΩ Parity ν obs a ν obs -ν calc a J+1←JΩ Parity ν obs a ν obs -ν calc a 24←23e281, e343, f281, f342, e283, e343, f284, f343, e284, e345, f284, f345, e285, ←29e b f285, f b ←24e292, e353, f292, f352, e293, e354, f294, f354, e295, e355, f295, f355, e296, e357, f296, f357, e297, ←30e362, f297, f b ←25e304, e364, f304, f365, e306, e366, f305, f366, e307, e367, f307, f367, e308, ←31e374, f308, f374, e309, e376, f309, f376, ←26e316, e377, f316, f378, e317, e379, f318, f379, e319, e380, f318, f380, e320, ←32e b f320, f b e321, e387, f321, f388, ←27e327, e390, f327, f389, e329, e392, f329, f392, e330, ←33e b f331, f b e331, e400, f331, f399, e333, e401, f333, f402, ←28e339, e b f339, f b e340, e404, f341, f404,

June 22-26, th International Symposium on Molecular Spectroscopy Hund’s case(a) Hamiltonian Ĥ eff = Ĥ rot + Ĥ so + Ĥ so (3) + Ĥ ss + Ĥ ss (4) + Ĥ  -doubling Parameter a,b v=0 B (59) D (66) H x (243) A x (1580) ADAD 27.64(41) AHAH (10) (o+p+q)8900(2700) (p+2q)2648(56) q-14.8(3.8) (o+p+q) D 1.72(69) (p+2q) D 0.155(29) qDqD (95) λ x (553) λDλD 5.10(27) λHλH (45) η x (480) ηDηD 11.27(61) θDθD -3.25(83) rms a In MHz; b Values in parenthesis are 3  errors and apply to last quoted digit = B (J-S) 2 – D (J-S) 4 + H (J-S) 6 + A (LS) + ½ A D {LS, (J-S) 2 } + ¼ A H {LS, (J-S) 4 } + η L z S z {S z 2 - (3S 2 -1)/5} + η D / 2 {L z S z [S z 2 -(3S 2 -1)/2], (J-S) 2 } + 2 / 3 λ (3S z 2 -S 2 ) + 1 / 3 λ D {(3S z 2 - S 2 )/ 3, (J-S) 2 } + 1 / 6 λ H {(3S z 2 -S 2 ), (J-S) 4 } + θ D / 24 {(35S z S 2 S z ZS z 4 - 6S 2 + 3S 4 ), (J-S) 2 } + ½ (o+p+q) (S + 2 +S - 2 ) – ½ (p+2q) (J + S + + J - S - ) + ½ q {(J J - 2 ) + ¼ (o+p+q) D {(S + 2 +S - 2 ), (J-S) 2 } – ¼ (p+2q) D {(J + S + + J - S - ), (J-S) 2 } + ¼ q D { (J J - 2 ), (J-S) 2 }

June 22-26, th International Symposium on Molecular Spectroscopy Interactions between rotational and electronic motions in a molecule Ground 5  r state interacting with nearby excited 5  state Splitting of two degenerate levels that are present when Λ ≠ 0 From Λ-doubling splitting and constants – learn something about the energy separation between electronic states Brown and Merer, J. Mol. Spec., 74, (1979) Λ-doubling Molecular Energy Levels Energy Bond distance X5rX5r 5 5

June 22-26, th International Symposium on Molecular Spectroscopy Λ-doubling 10  3d 3p 4s 12  11  44 55 11 X 5  r : [core] 10  2 4  4 11  1 1  2 5  1 5   : [core] 10  2 4  4 11  1 1  2 5  0 12  1 d  d  Cr S

June 22-26, th International Symposium on Molecular Spectroscopy Case of pure precession – Assumption that the molecular angular momentum L is fixed and precesses around the molecular axis Λ-doubling ≈ 950 cm -1 ≈ d  d  Brown and Merer, J. Mol. Spec., 74, (1979)

June 22-26, th International Symposium on Molecular Spectroscopy Conclusion and Future Directions Verified 5  r electronic ground state Established molecular parameters for all five spin components Estimated ~950 cm -1 energy separation between the ground 5  r electronic state and a nearby 5  excited electronic state Current focus → Titanium: – Finished TiS ( 3  r ) - FC11 – Future projects TiSH ( 4 A”) and TiOH ( 4 A”)

June 22-26, th International Symposium on Molecular Spectroscopy Acknowledgements Lucy Ziurys DeWayne Halfen Amanda Higgins Rest of Ziurys Group Emily TenenbaumMing Sun Lindsay ZackJessica Dodd Gilles AdandeJie Min Matthew BucchinoBrent Harris NSF and NASA - Funding