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Electronic transitions of ScP N. Wang, Y. W. Ng, K. F. Ng, and A. S.-C. Cheung Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong Paper - TK 04 International Symposium on Molecular Spectroscopy 69th Meeting - June 16-20, 2014 - Champaign-Urbana, Illinois

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Acknowledgements Graduate Students:Miss Na Wang Mr. Tony Y. W. Ng Mr. Ken Ng Funding Agents: Research Grants Council, HKSAR Committee on Research & Conference Grants, HKU

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Introduction Sc diatomic molecules are interesting: Spectroscopic interest: Sc : 4s 2 3d 1 atomic configuration With only one electron in the d orbital, it is an ideal system for studying chemical bonding of the d orbital

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Background F. Tiengeta & J. F. Harrison (1994) Chem. Phys. Lett., 223, 202. ~ performed MCSCF level calculations and predicted a X 1 + state and several low-lying 1 , 3 + and 3 electronic states. A. Daoudi, M. F. Baba S. Elkhattabi, F. Rogemond & H. Chermette (2003) Mol. Phys. 101, 292. ~ performed CASSCF, CIPSI, and DFT calculations and predicted the bonding of the X 1 + involve an open-shell state. G.M.S. Tong, G.H. Jeung and A.S-C. Cheung (2003) J. Chem. Phys. 118, 9224 ~ performed DFT calculations and predicted the spectroscopic properties of the X 1 + and a few low-lying excited states. Z. Liao, Y. Xia, M-C. Chan & A. S-C. Cheung (2012) Chem. Phys. Lett. 551, 60. ~ analyzed the LIF spectrum in the near IR region between 775.0 and 896.8 nm. ~ the [11.9] 1 + - X 1 + transition and determined the X 1 + ground state.

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Experimental technique: laser vaporization/reaction free jet expansion and laser induced fluorescence spectroscopy 2%PH 3 /Ar Sc rod

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Experimental Conditions Laser ablation reaction: Sc (atom) + 2% PH 3 / Ar ScP + etc. Ablation Laser: Nd:YAG, 10Hz, 532nm, ~5 mJ Gas Pressure: 6 atm (argon + reagent gas) Background pressure: 5x10 -5 Torr. Excitation Lasers: Optical parametric oscillator (OPO) system pumped by Nd:YAG Laser@ 355nm. A dye laser pumped by Nd:YAG laser

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Results and analysis: Two new electronic transition systems: the [19.0] 1 + - X 1 + and [19.8] 3 + - a 3 + transitions [19.0] 1 + [19.8] 3 + a3+a3+ Our apology: the [19.8] 3 - a 3 transition listed in the ABSTRACT is not correct. Earlier work

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The (3, 0) band of [19.0] 1 + - X 1 + Electronic Transition P branch R branch Only P and R branches

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Results from least squares fittings: The analysis included v= 0, 1, 3 and 4 The (2, 0) band overlaps with a triplet transition band The observed rotational lines were fitted to the expression: = o + B' J' (J' + 1) - D' [J' (J' + 1)] 2 - {B" J" (J"+ 1) D" [J"(J" + 1)] 2 } State v v 0 B [19.0] 1 + 4 20276.029(9) 0.16320(5) 3 20680.942(7) 0.16296(8) 1 19470.205(7) 0.16757(2) 0 19061.341(9) 0.1677(2)

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The (1, 0) band of [19.8] 3 + - a 3 + Transition R branches P branches

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(1, 0) band of [19.8] 3 + - a 3 + transition : This triplet transition: 1. Initially, lines were fitted to the expression: = o + B eff J (J + 1) - D eff [J (J + 1)] 2 - {B eff J (J + 1) D eff [J(J + 1)] 2 } 2. Effective Hamiltonian (Subsequently) RMS error = 0.05 cm -1 [19.8] 3 + v = 1 T 1 = 20392.678(9) B = 0.1417(3) = - 0.14(7) a3+a3+ v = 0 B = 0.1902(3) = 0.52(7)

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The (0,0) band of [19.8] 3 + - a 3 + transition is perturbed R branches P branches

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The (0,0) band of [19.8] 3 + - a 3 + transition is perturbed We could not fit all the lines to the 1. Effective Hamiltonian 2. The F 2 component is perturbed [19.8] 3 + v = 0 3 1 : T 0 = 19884.72(2) ; B = 0.1557(2) 3 0 : T 0 = 19884.98(3) ; B = 0.1515(2) a3+a3+ v = 0 B = 0.1902(3) = 0.52(7)

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The (0,0) band of [19.8] 3 + - a 3 + transition is perturbed Two perturbations were found for the F2 component of the upper state. at J = 10 and 22 Reduced term value plot vs N(N+1) showing the perturbations

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Resolved fluorescence spectrum of (0,0) band of [19.8] 3 + - a 3 + transition The G 1/2 the a 3 + state was estimated to be 495 15 cm -1

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Molecular constants determined for ScP (cm -1 ) State T0T0 B0B0 G 1/2 R e () [19.8] 3 + a + 19884.720.1557507.982.4297 [19.0] 1 + 19061.340.16757408.862.3421 [11.9] 1 + 11936.390.19678517.222.1613 a3+a3+ a0.1902495* 2.1984 X1+X1+ 00.18956494.872.2022 * Value estimated from resolved fluorescence spectrum a is the origin of the a 3 + state

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State ParameterExperimental Theoretical TH[1] DBERC[2]TJC[3] MCSCF CIPSI B-P86 DFT A 1 + or [11.9] 1 + T e B e e r e 11923.2 0.19721 521.2 2.1590 13829 0.1931 503 2.181 10644 0.1966 542 2.162 a 3 + T e B e e r e a 0.1902* 495* 2.1984* 6444 0.1771 413 2.278 6128 0.1856 442.6 2.226 7386 0.1909 489.7 2.194 X 1 + B e e r e 0.19001 494.9 2.1995 0.1773 446 2.277 0.1806 441.0 2.256 0.1915 521.6 2.191 0.1946 537 2.173 [1] F. Tiengeta & J. F. Harrison (1994) Chem. Phys. Lett., 223, 202. [2] A. Daoudi, M. F. Baba S. Elkhattabi, F. Rogemond & H. Chermette (2003) Mol. Phys. 101, 292 [3] G.M.S. Tong, G.H. Jeung and A.S-C. Cheung (2003) J. Chem. Phys. 118, 9224 Comparison of molecular constants for ScP cm -1 * B 0, G 1/2 and r 0

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Molecular Orbital and Electronic Configurations of ScP Configurations: X 1 + : 1 2 1 4 2 2 & 1 2 1 4 2 1 3 1 a 3 + : 1 2 1 4 2 1 3 1 A 1 + : 1 2 1 4 2 2 ScCl ScS 3 e 5 e

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Comparison of diatomic molecules of Sc and nearby main group elements ScP 1+1+ 12142131& 12142212142131& 121422 0.19001494.92.1995 ScN 1+1+ 12142131& 12142212142131& 121422 0.55461795.01.6870 ScO 2+2+ 1214223112142231 0.51340964.91.6682 ScS 2+2+ 1214223112142231 0.19717565.22.1288 ScCl 351+1+ 1214223212142232 0.17231447.52.2303 MoleculeGround state Electronic Config. B e /cm -1 e /cm -1 R e ()

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Summary 20 (1)A new triplet [19.8] 3 + - a 3 + transition has been recorded and analysis. (2)The bond length of the ground X 1 + state of ScP is relatively long, which agrees well with theoretical value from admixture of 1 2 1 4 2 1 3 1 & 1 2 1 4 2 2. (3)The a 3 + state has similar bond length, which should also be arisen from the 2 1 3 1 configuration as in the ground state.

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Thank you