1. Coherent Synchrotron Radiation for Rotational Spectroscopy : application to Propynal in the 200-750 GHz range J.Barros P.Roy L.Manceron SOLEIL - AILES beamline - France D.Apadoo, D. McNaughton E. Robertson Australian Light source and Monash U.

2. Outline Introduction 1. CSR generation 2. Adaptation to AILES beamline 3. Noise correction 4. Use of CSR for measurements on Propynal MSS Columbus 2013

3. High Resolution IR spectroscopy with Synchrotron Radiation Introduction Synchrotron beam Bruker 125HR Interferometer resolution: 0.001 cm -1 Bolometer path difference wavenumber Fourier Transfo rm MOPD 8.82 m Fixed mirror Moving mirror 1 MSS Columbus 2013

4. 10 Emission modes 1. CSR generation N≈10 8  <  z incoherent emission Emission mode 4 MSS Columbus 2013

5. N≈10 8 10  <  z incoherent emission Emission mode Emission modes  ≥  z coherent emission CSR 1. CSR generation 4

6. “Clearly the promise of a bright, high-power THz continuum source is attractive. However, we note that CSR is itself a non-linear effect and so may tend to be inherently noisy.” R. W. McKellar, J. Mol. Spectrosc. 262, 1 (2010) «High Resolution IR spectroscopy with synchrotron radiation»

7. CSR instabilities Microbunching: interaction of an electron bunch with its own emitted radiation  Bunch profile modulation C. Evain, J. Barros et al., EPL 98, 40006 (2012) 1. CSR generation 5 MSS Columbus 2013

8. CSR instabilities Microbunching: interaction of an electron bunch with its own emitted radiation  Bunch profile modulation C. Evain, J. Barros et al., EPL 98, 40006 (2012) 1. CSR generation 5 MSS Columbus 2013

9. CSR instabilities Microbunching: interaction of an electron bunch with its own emitted radiation  Bunch profile modulation C. Evain, J. Barros et al., EPL 98, 40006 (2012) 1. CSR generation Flux scales with N N≈10 8  <  z incoherent emission Emission mode  ≥  z coherent emission scales with N² Microstructures emit coherently very irregular 5 MSS Columbus 2013

10. Effect of increasing current No detected CSR 2. Adaptation to the AILES beamline 6 MSS Columbus 2013

11. Effect of increasing current No detected CSR CSR appears Gain in intensity: 10 4 to 10 5 2. Adaptation to the AILES beamline 6 MSS Columbus 2013

12. Effect of increasing current No detected CSR CSR appears Gain in intensity: 10 4 to 10 5 Microbunchi ng instability 2. Adaptation to the AILES beamline 6 MSS Columbus 2013

13. Effect of bunch length Stability zone in bunch length and current 2. Adaptation to the AILES beamline 7 MSS Columbus 2013

14. Broadband source, but still some remaining noise at given frequencies Effect of microbunching evidenced even under threshold2 2. Adaptation to the AILES beamline Signal spectral distribution Noise frequencies 9 MSS Columbus 2013

15. Noise correction setup Synchrotron beam Bruker 125HR Interferometer Bolometer 1 Interferogram + perturbation 3. Noise correction 11 MSS Columbus 2013

16. Noise correction setup 3. Noise correction Synchrotron beam Bruker 125HR Interferometer Bolometer 1 Interferogram + perturbation 6 µm Mylar beamsplitter R/T≈0,2 Bolometer 2 Perturbation only 11 MSS Columbus 2013

17. Noise correction setup 3. Noise correction 4.2 K composite bolometers with identical 0-200 cm -1 filters, same solid angle, same preamplifiers Simultaneous acquisition 4.2 K composite bolometers with identical 0-200 cm -1 filters, same solid angle, same preamplifiers Simultaneous acquisition Synchrotron beam Bruker 125HR Interferometer Bolometer 1 Interferogram + perturbation 6 µm Mylar beamsplitter R/T≈0,2 Bolometer 2 Perturbation only Post-treatment: subtraction of the 2 temporal signals  FT 11 MSS Columbus 2013

18. Correction examples Periodic perturbation Artifact on an absorbance spectrum  compensated White noise correction Aperiodic, bursting perturbation Top-up correction: effect on spectrum 3. Noise correction 12 MSS Columbus 2013

19. Correction examples 3. Noise correction Example on a 45 min spectrum Res = 0.001 cm -1 Pure rotational line of N 2 O with an intensity of 9.0∙10 -23 cm - 1 /(moleculexcm ² )  Gain of 5 in S/N J. Barros and coll. Rev. Sci. Inst. 84, 033102(2013) 13 MSS Columbus 2013

20. Application Rotational spectrum of propynal 0.225 mbar in 885 cm, 9h, bolometer 4.2 K About 1200 pure rotational transitions in the ground state Previous works: Winnewisser, 1972 (90 transitions) McKellar (IR combination differences) Fit of the ground state (Watson a- type Hamiltonian) 4. Propynal 15 MSS Columbus 2013

21. Application Rotational spectrum of propynal 0.225 mbar in 885 cm, 9h, bolometer 4.2 K 4. Propynal 14

22. Application J=38 → 39 J=39 → 40 not present in the fit Spectrum Simulati on 4. Propynal 16 MSS Columbus 2013

23. Some improvements in the molecular constants MSS Columbus 2013 Constants this work (MHz) Winnewisser (MHz) McKellar et al. (MHz) Rotational A B C a 68035,308 (025) b 4826,28805 (097) 4499,52695 (095) 68035,299 (043) 4826,3014 (073) 4499,5107 (069) 68035,263 (039) 4826,293 (006) 4497,15 (006) Centrifugal Distorsion Quartic Δ J Δ JK Δ K δ J δ K a 1,91792 (111) · 10 -3 a -0,1481185 (186) a 9,0033 (057) a 3,37419 (151) · 10 -4 b 0,03396 (026) 1,917 (012) · 10 -3 -0,148102 (047) 8,991240 (9730) 3,458 (014) · 10 -4 0,019500 (1590) 1,913 (004) · 10 -3 -0,148044 (039) 8,993 (009) 3,454 (012) · 10 -4 0,0347 (028) Sextic H JK H KJ H K H J -0,8348 (082) · 10 -6 b -8,245 (107) · 10 -6 3,190 (147) · 10 -3 7,549 (214) · 10 -9 -7,41 (059) · 10 -7 -8,310 (130) · 10 -6 -- -7,11 (048) · 10 -7 -8,24 (012) · 10 -6 2,36 (006) · 10 -3 --

24. Conclusions Extension of SR spectral range at SOLEIL BUT Limited Resolution (30MHz..) - Time-saving for studies of unstable molecules - Combination with IR studies on the same setups - Intensity studies are possible Frequency 0.1 THz 1 THz10 THz100 THz ISR High res. Wavenumber 3.3 cm -1 33 cm -1 330 cm -1 3300 cm -1 CSR High res. 17 MSS Columbus 2013

25. Two important WEB Pages : http://www.synchrotron-soleil.fr/ For general informations http://www.synchrotron- soleil.fr/portal/page/portal/Recherche/LignesLumiere/AILES and, for proposal submissions : http://sunset.synchrotron-soleil.fr/sun/ twice a year : mid-september and –february deadlines. Proposals (submissions in English) ranked by an international peer-review committee. How to submit your proposals Support from User Office Preparing your experiment Safety requirements Beamline AILES: Mid IR to THz Spectroscopy

26. Acknowledgements Lille: Clément Evain Serge Bielawski Christophe Szwaj SOLEIL- Machine: Marie-Emmanuelle Couprie Marie-Agnès Tordeux Pascale Brunelle Laurent Nadolski Alex Loulergue Marie Labat Lodovico Cassinari Ryutaro Nagaoka Amor Nadji MSS Columbus 2013