1. Laboratory of Millimetre-wave Spectroscopy of Bologna The ROTATIONAL SPECTRUM of HDO : ACCURATE SPECTROSCOPIC and HYPERFINE PARAMETERS G. Cazzoli*, V. Lattanzi*, C. Puzzarini*, J. Gauss # *Dip. Chimica “Giacomo Ciamician” Università di Bologna # # Institut für Physikalische Chemie, Universität Mainz 69th Meeting - June 16-20, 2014 Champaign-Urbana, Illinois

2. 69th Meeting - June 16-20, 2014 Champaign-Urbana, Illinois

6. 69th Meeting - June 16-20, 2014 Champaign-Urbana, Illinois

7. Submitted ABSTRACT

8. Laboratory of Millimetre-wave Spectroscopy of Bologna Working frequency range: 65 GHz – 1.6 THz

9. Laboratory of Millimetre-wave Spectroscopy of Bologna Measurements: Lamb-dip technique using free-space cell G. Cazzoli & L. Dore, J. Mol. Spectrosc. 143, 231 (1990)

10. Laboratory of Millimetre-wave Spectroscopy of Bologna H 2 S: J = 8 6,3 – 8 5,4 > 4 MHz Lamb-dip in the THz

11. Laboratory of Millimetre-wave Spectroscopy of Bologna H 2 S: J = 8 6,3 – 8 5,4 ~100 kHz Cazzoli & Puzzarini, J. Phys. Chem. A 117, 13759 (2013)

12. Laboratory of Millimetre-wave Spectroscopy of Bologna D 2 O: J = 3 2,2 – 3 1,3 50 kHz F = 3 - 3 F = 4 - 4 F = 5 - 5

13. 69th Meeting - June 16-20, 2014 Champaign-Urbana, Illinois

16. NO hyperfine structure

17. Hyperfine structure due to D

18. Hyperfine structure: effect of H

19. Hyperfine structure: inclusion of spin-spin coupling

20. Experiment

21. Calc: full HFS ? ?

22. Experiment Calc: “real” + “ghost”

25. Results ParameterEXPAB INITIO Χ aa (D) / MHz0.2772(12)0.281 Χ bb (D) / MHz-0.1063(38)-0.105 Χ cc (D) / MHz-0.1709(38)-0.176 C aa (D) / kHz -1.19(18) -1.05 C bb (D) / kHz-4.63(20) -4.39 C cc (D) / kHz-3.78(16)-3.48 C aa (H) / kHz-57.95( 40)-57.02 C bb (H) / kHz-9.59(37)-8.52 C cc (H) / kHz -22.72( 57)-22.47 S aa (H-D) / kHz-8.33(59)-8.40 Level of Theory Geometry Geometry: semi-exp r e Equilibrium Equilibrium: all-CCSD(T)/aug-cc-pCV6Z Vibrational Correction Vibrational Correction: all-CCSD(T)/aug-cc-pCV5Z

26. Results ParameterEXPAB INITIO Χ aa (D) / MHz0.2772(12)0.281 Χ bb (D) / MHz-0.1063(38)-0.105 Χ cc (D) / MHz-0.1709(38)-0.176 C aa (D) / kHz -1.19(18) -1.05 C bb (D) / kHz-4.63(20) -4.39 C cc (D) / kHz-3.78(16)-3.48 C aa (H) / kHz-57.95( 40)-57.02 C bb (H) / kHz-9.59(37)-8.52 C cc (H) / kHz -22.72( 57)-22.47 S aa (H-D) / kHz-8.33(59)-8.40

27. Hyperfine structure only due to D with SR of D without SR of D

28. Hyperfine structure only due to D ~ 4 kHz

30. Other Results Spectroscopic Parameters Rotational Constants Rotational Constants: Uncert. = 4-10 kHz Centrifugal Distortion Const. Centrifugal Distortion Const.: up to octics (a few decics)

31. Future Work 500 – 1600 GHz Lamb-dip Measurements up to 1.2 THz (strong lines) Improved Doppler-limited Measurements: up to 1.6 THz (weak lines)

32. Laboratory of Millimetre-wave Spectroscopy of Bologna THANK YOU For YOUR ATTENTION THANKS $$$$$$: MIUR & University of Bologna