1. Ivan O. Antonov, Michael C. Heaven Emory University, Department of Chemistry 1515 Dickey Drive, Atlanta GA 30322

2.  Nuclear waste disposal and reprocessing

3. (I. Infante et al. JCP, 127, 124308 (2007)) DG 1/2 = 914 cm -1 (Ne), 776 cm -1 (Ar) Ground state configuration 5f7s  5f 2 (Zhou, Andrews, Ismail & Marsden JPCA, 104, 5495 (2000)) 5f7s 5f 5/2 5f 7/2 Ω=2 Ω=3 Ω=4 How widely are the 3 Φ u and 3 H g states split???

4. UO 2 exhibits delayed ionization near the IP threshold Extremely large density of states!!! ZEKE spectrum of UO 2 + is highly congested (Merritt J.M., Han J., Heaven M.C., JCP, 128, 084304 (2008))

5.  Dispersed fluorescence from previously observed electronically excited states  1+1’ REMPI with first photon in red-NIR  SEP spectroscopy

6. 1064 nm, 26 mJ He with 0.1% O2 Ablation Probe laser(s) PMT MCP Probe laser TOF mass-spec Oscilloscope Monochromator Ablation laser

7. X 3Φg3Φg Emission Excitation V=1

8. X 3Φg3Φg Excitation 2 nd order of monochromator Emission

9. X 3Φg3Φg Tunable ND:YAG pumped dye laser t Fluorescence SEP allows probing the ground state SEP on UO2 failed due to state mixing!

10. X UO 2 + +e Tunable ND:YAG pumped dye laser 248 nm KrF

11. (I. Infante et al. JCP, 127, 124308 (2006)) ExperimentIHFSCC 40 e 2 900 – 4 700 cm -1 1 u at 2 231 cm -1 2 u at 2 588 cm -1 4 u at 5 047 cm -1 7 400 cm -1 2 u at 7 431 cm -1 10 900 cm -1 4 g at 10 914 cm -1 11 500 cm -1 0 g at 11 436 cm -1 12 200 cm -1 1 g at 12 564 cm -1 12 900 cm -1 2 g at 12 958 cm -1 13 600 cm -1 1 g at 13 919 cm -1 14 300 cm -1 1 g at 13 919 cm -1 or 5 g at 15 408 cm -1

12.  UO2 molecule was studied by REMPI at 10800 – 14600 cm -1 and by dispersed fluorescence on 31800 cm -1 and 27100 cm -1 transition  New excited states were found and preliminarily assigned at 2900-4700 cm -1, 7400 cm -1 and 10900-14300 cm -1 region  Excited state mixing phenomena is responsible for severe line broadening and background signal; It prevents from obtaining rotationally resolved spectra of UO2

13.  1+1’ REMPI with OPO/OPA system in mid-IR X UO 2 + +e OPO/OPA Tunable ND:YAG pumped dye laser at ~ 210-220 nm

14. Vladimir E. Bondybey for help with experiment Group members: Beau Barker, Jiande Han, Keith Freel and Humayun Kabir Prof. Michael Heaven DOE for funding!!!