1. First results from the far-infrared beamline at the Canadian Light Source: High resolution analysis of acrolein in the 600 cm -1 region A.R.W. McKellar National Research Council of Canada D.W. Tokaryk, L.-H. Xu University of New Brunswick D.R.T. Appadoo, T. May Canadian Light Source Centre for Laser, Atomic, and Molecular Sciences University of New Brunswick

2. First results from the far-infrared beamline at the Canadian Light Source: High resolution analysis of acrolein in the 600 cm -1 region A.R.W. McKellar National Research Council of Canada D.W. Tokaryk, L.-H. Xu University of New Brunswick D.R.T. Appadoo, T. May Canadian Light Source

3. Canadian Light Source Saskatoon, Saskatchewan

4. Where is Saskatoon?

5. CLS Parameters Energy: 2.9 GeV Current: 200 mA Circumference: 171 m 12 straight sections, 5.2 m long RF: 500 MHz, 2.4 MV, supercon Injection: 250 MeV LINAC full energy booster ring Main building: ~ 85 x 85 m

6. Synchrotron IR There are two infrared beamlines at CLS: 1) Far IR (this talk) 2) Mid IR spectromicroscopy (biological / industrial samples) All other CLS beamlines are for x-rays The synchrotron simply replaces the normal source (globar), providing continuum IR radiation to a conventional FTIR spectrometer The high brightness of synchrotron radiation is ideal for the small entrance aperture required for high spectral resolution Bruker IFS 125 HR spectrometer: max optical path difference = 9.4 m; instrumental resolution ~ 0.0008 cm -1 (24 MHz)

7. Energy / cm -1 SR 23 SR 27 Hg SR 27 /Hg SR 23 /Hg (SR is normalized to 202 mA) SR 23 : Synch. Radiation Run 23 SR 27 : Synch. Radiation Run 27 Hg: internal Hg lamp Synchrotron brightness advantage (the good news)

8. SR 23 Hg Synchrotron noise (the bad news)

9. Clearly signal-to-noise ratio is the important factor Our problem is mechanical vibrations in the optics that bring IR radiation from the storage ring to the spectrometer Ring Source Diamond Window Spectrometer Shielding Wall

10. With successive improvements, the synchrotron now has a significant advantage over the globar from 250 ~ 800 cm -1 But we are aiming for much better performance Reduce noise at source: better isolation of offending cooling pumps, heat exchangers, pipe runs, etc. Reduce noise at beamline: more isolation, better mounting of mirrors Active optics to stabilize the input radiation on the spectrometer aperture

11. Acrolein CH 2 CHCHO A 1.57955 B 0.15542 C 0.14152 fundamental 8-atom species planar near-prolate asymmetric rotor interstellar molecule combustion byproduct (cigarette smoke) potent respiratory irritant (smog)

12. 17 band of acrolein, CH 2 CHCHO K a = 7 – 6 Q-branch nominal resolution 0.0012 cm -1

13. Acrolein: center of the 17 band

14. Acrolein: q Q-branch, center of the 12 band

15. Acrolein: local perturbation of 17 K a = 13 levels around J = 30, explained by crossing with K a = 13 of 4 18

16. 12 17 4 18 Ground state v0v0 564.3404(1)593.0793(1)621.958(16) A1.5789146(15)1.5768182(12)1.384325(23)1.57954976 B0.1553289(44)0.1552016(44)0.1562836(42)0.155424164 C0.14136381(15)0.14150373(10)0.1436751(42)0.141520893 10 5 x D K 1.23410(33)1.18322(26)-8.303(57)1.20053 10 7 x D JK -3.2434(74)-2.8887(20)-2.92953 10 8 x D J 3.4938(71)3.5101(30)3.47417 10 7 x  K 2.18(17)2.09(10)1.9342 10 9 x  J 3.855(63)3.917(33)3.99773 10 10 x H K -7.827(49) G a (12,17) 0.251076(75) G b (12,17) 0.0454(14) 10 5 x Z 1 (12,17) -6.039(37) 10 4 x Z 3 (12,17) -4.29(68) 10 3 x G a (17,18 4 ) 6.533(24) 10 7 x Z 5 (17,18 4 ) -4.17(25) Acrolein: ~2000 lines of the 12 & 17 bands represented in terms of 25 parameters (including ‘dark’ state 4 18 )

17. Acrolein: local perturbations of K a = 8 and 14 levels of 17 remain unexplained

18. Acrolein: recently we also studied the 18 fundamental band at 158 cm -1

19. Acrolein 18 central region

21. 18 Ground state* v0v0 157.8835(1) A1.5271603(10)1.57954976 B0.15564972(21)0.155424164 C0.14208563(17)0.141520893 10 5 xDKDK -0.2143(8)1.20053 10 7 xD JK -2.890(8)-2.92953 10 8 xDJDJ 3.642(7)3.47417 10 7 x KK -0.08(20)1.9342 10 9 x JJ 4.11(5)3.99773 10 9 xHKHK -7.944(28) 10 10 xH KJ 6.6(31)-0.1586 10 12 xLKLK 2.824(27) * Winnewisser, Winnewisser, Honda, & Hirota, Z. Naturforsch. 30a, 1001 (1975) Acrolein 18 parameters

22. High-resolution synchrotron IR Previous results from MAXlab and LURE were promising -- we hope to do better Presently at CLS: 100 – 200 cm -1 region: SR is ~ 4 times better 250 – 700 cm -1 region: SR is ~ 8 times better Other new synchrotrons (SOLEIL, Australia, Switzerland, Singapore,...) are building hi-res IR facilities Are we the first synchrotron user facility for high- resolution IR spectroscopy of gases ?