Search for a parity violation in the spectrum of molecules : new perspectives

1. Search for a parity violation in the spectrum of molecules : new perspectives C. Chardonnet, C. Stoeffler, B. Darquié , A. Shelkovnikov, C. Daussy, A. Amy-Klein Laboratoire de Physique des Lasers 99 av.J.-B. Clément, 93430 Villetaneuse, FRANCE

2. Introduction: parity violation in chiral molecules Parity violation: 123456789 123456789 123456789

3. Introduction: parity violation in chiral molecules = = 0 In atomic physics M.A. Bouchiat and C. Bouchiat, Phys. Lett. 48B, 111-114 (1974) In molecular physics D.W. Rein, J. Mol. Evol. 4, 15-22 (1974)

4. Introduction: parity violation in chiral molecules E1R Rovibrational energy E1L hnR hnL E0R E0L CHFClBr 1975: Due to parity violation, two enantiomers do not have the same absorption spectrum [V.S. Letokhov, Phys. Lett. 53A, 275 (1975)] n L nR 1976 : Proposition to search for parity violation effect in CHFClBr spectrum [O.N. Kompanets et al., Opt. Commun. 19, 414 (1976) ]

5. Introduction: parity violation in chiral molecules D n 1977: Test on the resolved enantiomers of camphor [E. Arimondo et al. Opt. Commun. 23, 369 (1977)] 2004: Theoretical estimation of PV effect in camphor spectrum [P. Schwerdtfeger et al., Chem. Phys. Lett. 383, 496 (2004)]

6. 5 MHz 90 kHz 5 kHz 18 kHz 1 cm-1 = 30 GHz 10 GHz CF-stretching fundamental n4 of CHF35Cl81Br cm-1 F.T. Spectrum (A. Valentin) 1074.4 1074.6 1074.8 rovibrational lines: (40,7,34)(40,8,33) (49,10,39)(49,11,38) saturation spectrum in a Fabry-Perot cavity 1.7 10-7 cm-1 saturation spectrum in a 18 m-long cell T. Marrel et al., Journal of Molecular Structure 599, 195-209 (2001)

7. The experimental setup CO2 laser

8. Results Mean value : -4.2 Hz standard deviation : 16 Hz N=780 measurements 150 100 50 0 -200 -100 0 100 200 frequency difference (-) - (+) (Hz) Systematic effect (collisional shift) RESULT: C. Daussy et al., Phys. Rev. Lett. 83, 1554-1557 (1999) M. Ziskind et al.,Euro. Phys. J. D 20, 219-225 (2002)

9. Results Frequency difference (-) - (+) versus pressure 40 30 20 Frequency difference (-) -(+) (Hz) 10 0 0 0.5 1 1.5 2 2.5 3 3.5 4 CHFClBr pressure in both cavities (x 10-3 mbar)

10. Conclusion of these first tests Result Improvement of 5 orders of magnitude limitations • Sensitivity limited by collisions • @ 2.5.10-13 Molecular beam no collisional effect • linewidth ~ 60 kHz Ramsey Fringes spectroscopy Linewidth : 100-1000 times narrower • Calculated effect (1-3)~ 2.4 mHz (810-17) New molecule with stronger effect (1) M. Quack et al., J. Chem. Phys. 119, 11 228 (2003) (2) P. Schwerdtfeger et al., Phys. Rev. A 71, 012103 (2005) (3) R.G. Viglione et al., Phys. Rev. A 62, 052516 (2000)

11. a new experimental scheme: Doppler free two photon Ramsey spectroscopy w w supersonic beam + two-photon Ramsey fringes spectroscopy Laser zone 1 Laser zone 2 D/u : transit time between zones molecules 2w 2w Molecular beam Mean velocity u D Resolution

12. Experimental developments:the supersonic beam of SF6 pure or He-seeded Rotational cooling  10 K Flux  1012 molecules/s Beam velocity: 400 m/s

13. Central fringe of the SF6 signal 100 Hz S/N1Hz = 20 Amlpitude (arb. u.) Frequency detuning (50 Hz/div) Resolution = 310-12 Next problem  accuracy:  (2n3, P(4) E0) = 28 412 764 347 323.0 1.4 Hz A. Shelkovnikov et al., IEEE J. of Quant. Elect. 40 (8), 1023 (2004)

14. Toward a first observation of PV effect in molecules :a new molecule Re(5-Cp*)(=O)(CH3)Cl P. Schwerdtfeger et al., J. Am. Chem. Soc. 126,1652 (2004) • P. Schwerdtfeger et al., Phys. Rev. A 65, 042508 (2002) • R. Bast et al., Phys. Rev. Lett. 91, 023001 (2003)

15. Re(5-Cp*)(=O)(CH3)Cl a magic molecule ? • Advantages : • High NCP effect • Easy to synthesize each enantiomer with 100% efficiency • Preparing several tens of grams is feasible • Inconveniencies • Solid at room temperature (sublimation @ 120°C) • Unfavorable partition function (32 atoms, Matom=350 g)  laser ablation or heating and transported by a gas carrier in a supersonic beam Still some reflection on the choice of the best molecule

16. A new family of chiral molecules based on MTOthe methyltrioxorhenium Efficient sublimation around 100°C Chemistryperformed by J. Crassous and L. Guy vibrational PNC of 400mHz for Re-CH3-S-Se-O (calculated by T. Saue)

17. Hyperfine structure of a rotational transition of MTO in a supersonic beam (by T. Huet, Lille)

18. FT spectroscopy on a molecular beam of MTO(P. Asselin, P. Soulard @ UPMC – Paris) RQJ(0) RQJ(3) PQJ(3) PQJ(6) RQJ(6)

19. Saturated absorption spectrum in a cell (at LPL)

20. hyperfine structure of a rovibrational spectrum of MTO in a cell at room temperature (Scan of 10 MHz)

21. Detail of the hyperfine structure of MTO in a cell 36.9 37.0 37.1 37.2 Exp. Conditions: P= 10 -3 mbar FWHM=60 kHz 2nd harmonic detection Laser Power : a few µW Saturated absorption signal (u.a.) frequency (MHz)

22. First rovibrational signal of MTO in a supersonic beam seeded with He 4.4 4.0 Linear absorption (a.u.) 3.6 3.2 20 30 40 50 60 70 80 frequency (MHz) CO2 Laser AOM(s) photodetector Ø nozzle = 200 µm Ø skimmer = 2mm

23. A theoretical and experimental program involving 6 groups -Peter SCHWERDTFEGER Theoretical Chemistry AUCKLAND (New Zealand) - TrondSAUE, RadovanBAST Laboratoire de Chimie Quantique et Modélisation Moléculaire STRASBOURG (France) - JeanneCRASSOUS, LaureGUY Laboratoire de Chimie de l’ENS LYON (France) - ThérèseHUET Laboratoire de Physique des Lasers, Atomes, Molécules LILLE (France) - PierreASSELIN, PascaleSOULARD Laboratoire de Dynamique, Intéraction et Réactivité PARIS (France) - Benoît DARQUIE, Alexandr SHELKOVNIKOV, AnneAMY-KLEIN, CC Laboratoire de Physique des Lasers VILLETANEUSE (France)

24. Thank you for your attention ! Work supported by: CNRS, ANR (contracts NCPMOL 2006-2009 and NCPCHEM 2011-2014)