1. PURE ROTATIONAL SPECTRA OF THE REACTION PRODUCTS OF LASER ABLATED THORIUM METAL AND OXYGEN MOLECULES ENTRAINED WITHIN SUPERSONIC EXPANSIONS OF NOBLE GASES. *Brittany E. Long and ǂ Stephen A. Cooke RC02 June 20, 2013 * ǂ

2. Thorium α emitter t 1/2 = 1.4 E 10 years Solid at 25˚C MP= 1750 ˚C BP= 4820 ˚C 2

3. Fourier Transform Microwave Spectrometer at Wesleyan 3

4. Laser Ablation 4

5. THE MOLECULES 5

6. Calculations MP2 calculations with aug-cc-pVQZ for main group elements and a multi-electron, quasi-relativistic, effective core potential, ECP60MWB for thorium ThS, ThS 2, ThOC, ThOS, ThCS, For comparison reasons with HfO 2, ThO 2 was calculated with a B3LYP with aug-cc-pVQZ for O and an ECP60MWB for thorium for ThO 2 6

7. ThS Obtained B value from Professor Michael Heaven. B= 0.111(2) cm -1 or 3328(60) MHz 1,2 Using ν=2B(J+1) Transitions should be as follows: J 1 0 at 6656(120) MHz J 2 1 at 13312(240) MHz J 3 2 at 19968(480) MHz No ThS signal found on either the chirp or cavity with OCS or H 2 S as sulfur source. Searched 6 GHz with the chirp Searched 200 MHz twice with the cavity 1.Bartlett, J. H.; Antonov, I. O.; Heaven, M.C. Spectroscopic and Theoretical Investigations of ThS and ThS +. Manuscript in progress. 2.Bartlett, J. H.; Heaven, M. C. Ionization Measurement and Spectroscopy of ThS and ThS +. WK15 7

8. Measured J= 1 0 Rotational Transitions for Excited Vibrational States of ThO IsotopevFrequency/MHz 232 Th 16 O819273.9055 919194.3480 1019114.6205 1119034.7216 1218957.6471 1318874.3954 1418793.9657 1518713.3510 8

9. Previous Dunham Analysis 1 ParameterValue Y 01 /MHz9971.7767(35) U 01 /MHz149242.742(52) Y 11 /MHz-39.05256(26) Y 21 /MHz-0.039573(33) Δ O 01 -5.970(11) eQq( 17 O) v=0 /MHz2.827(9) eQq( 17 O) v=1 /MHz2.815(9) C I ( 17 O) v=0 /MHz-0.0108(5) C I ( 17 O) v=1 /MHz-0.0110(5) r e BO /Å1.84018613(24) 1. Dewberry, C. T.; Etchison, K. C.; Cooke, S. A. The pure rotational spectrum of actinide-containing compound thorium monoxide. Phys. Chem. Chem. Phys. 2007, 9, 4895-4897. 9

10. ThO Vibrational Temperature Vibrational temperature≈ 3300 K ThO vibrational frequency is 895.77(2) cm -1 [1] [1] Edvinsson, G.; Selin, L. E.; Aslund, N. On the band spectrum of ThO. Arkiv Fӧr Fysik. 1965, 30, 283-319. 10

11. 4 Thorium Dependent Transitions Possible Quantum NumbersFrequency/ MHz 3 03 -2 12 19251.8738 1 10 -1 01 14628.0470 2 11 -2 02 16140.3822 3 12 -3 03 18585.1238 Laser dependent Better signal with O 2 present Visible still in Neon Believed to be ThO 2 11

12. Adventures in Fitting 12 #Quantum NumbersFrequency /MHz 13 03 -2 12 19251.87381 21 10 -1 01 14628.04700 32 11 -2 02 16140.38217 43 12 -3 03 18585.12377 1, 2 and 31, 2 and 41, 2, 3 and 4 A19190.8879(56)19194.5467(42)19197.6395(37) B5968.89803(95)5967.37883(61)5967.68532(58) C4562.84090(299)4566.49974(141)4567.116531(135) RMS /MHz0.0 2.4 P CC /amu Å 2 0.1216620.1743020.177479

13. How to Proceed If ThO 2, 3 more possible transitions in range of spectrometer Currently waiting on 18-26.5 GHz low noise amplifier Repair of 5 W solid state amplifier Quantum NumbersPredicted Frequencies/MHz 2 02 -1 11 7734 4 13 -4 04 22181 1 11 -0 00 23764 13

14. Comparisons Bond Length/ ÅBond Angle/ ˚Ground StateCitation HfO1.7231481NA 1Σ1Σ1 HfO 2 1.7764(4)107.51(1) 1 A 1 -C 2v sym.1 ThO1.84018613(24)NA 1Σ1Σ2 ThO 2 1.897118.3 31 A 1 -C 2v sym.This work 1.Lesarri, A.; Suenram, R. D.; Brugh, D. Rotational spectrum of jet-cooled HfO and HfO 2. J. Chem. Phys. 2002, 117, 9651-9662. 2.Dewberry, C. T.; Etchison, K. C.; Cooke, S. A. The pure rotational spectrum of actinide-containing compound thorium monoxide. Phys. Chem. Chem. Phys. 2007, 9, 4895-4897. 3.Andrews, A.; Gong, Y.; Liang, B.; Jackson. V. E.; Flamerich, R.; Li, S.; Dixon, D. A. Matrix Infrared Spectra and Theoretical Studies of Thorium Oxide Species: ThO x and Th 2 O y. J. Phys. Chem. A. 2011, 115, 14407-14416. (116.47˚) 14

15. Comparisons Continued Hf: [Xe]4f 14 5d 2 6s 2 Th: [Rn]6d 2 7s 2 <118˚ 107.51(1)˚ 15

16. 2 nd Highest Occupied MOs 16

17. Conclusion Obtained the v=8-15 vibrational levels for ThO Predicted a vibrational temperature of about 3300 K Observed 4 thorium dependent transitions Most likely ThO 2 Provided interesting comparison between HfO 2 and ThO 2 Provide information via microwave spectroscopy to help advance the field of actinide chemistry 17

18. Future Work Finish ThO 2 Thorium with 18 O 2 and 17 O 2 as well Higher ThO vibrational levels of all species Revisit the Dunham analysis ThS and other thorium species Possible problems High omega values Out of range of spectrometers 18

19. Acknowledgements Novick, Pringle and Cooke Group Laboratory Funding from the DOE 19

20. LUMO 20

21. Novick Lab Picture 21