1. Mass-Analyzed Threshold Ionization of Lu 2 Lu Wu, Mourad Roudjane, Dong-Sheng Yang Department of Chemistry University of Kentucky Lexington, KY, 40504,USA 1

2. Previous Studies Zero Electron Kinetic Energy (ZEKE) spectrum of Y 2 – Y 2 : – Y 2 + : Mass Analyzed Threshold Ionization (MATI) spectrum of La 2 – La 2 : – La 2 + : Liu et. al., J. Chem. Phys., 135 (2011) 034309 Yang et. al., Int. J. Mass Spectrom. Ion Process. 159 (1995) 203 2

3. 39 Y 57 La 71 Lu 21 Sc Y: 4d5s 2 La: 4f 0 5d6s 2 Lu: 4f 14 5d6s 2 Sc: 3d4s 2 3

4. Previous Studies Experiment – Thermochemistry ： – Matrix-isolated Raman: Calculations – Ground state Fang et. al.,J. Chem. Phys., 22 (2000) 10202 K. A. Gingerich, Faraday Symp. Chem. Soc., 14 (1980) 109 Dolg et. al., Theor. Them. Acc., 108 (2002) 143 Ions? No Previous Studies 4

5. MATI Experimental Setup Pulsed Valve and Rod Source Carrier Gas Mixture He/Ar Extraction Can MCP  -Metal Shielding Turbo pump Diffusion Pump HV GV TOF 320 V/cm Source ChamberDetection Chamber Laser ablation 5

6. Theoretical Methods Calculations – Multi-configuration methods: CASPT2 CAS (6,18) – Basis set: ANO-RCC – Relativistic effect: Douglas-Kroll-Hess Hamiltonian; spin orbit coupling – Program: MOLPRO 2010 6

7. 0-0 MATI of La 2 MATI of Lu 2 7

8. Vibrational Frequencies: Lu 2 : Lu 2 + : 91 MATI of Lu 2 139 121 0-0 Ionization Energies: 42955 cm -1 (UPPER LIMIT) 44851 cm -1 8 135 121 45068 cm -1 0-0

9. Energy 0 2957 5403 44387 45897 Freq. (cm -1 ) 140 88 151 123 129 43683 45091 9 42955 cm -1 (UPPER LIMIT) 44851 cm -1 45068 cm -1 IONIZATION ENERGYFREQUENCIESTRANSITION

10. Lu 2 La 2 Y2Y2 2.69 2.98 2.94 2.85 2.70 2.65 3.37 Electron Removed 5dπ u 6sσ g 5dπ u 5sσ u Neutrals Ions R (Å) E-state 2.92 6sσ u 10

11. Comparison of Y, La and Lu Δ (eV) YLaLu 1.3560.3302.510 11

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