The GHz and THz spectrum of monodeuterated oxirane

The GHz and THz spectrum of mono-deuterated oxirane D S. Albert, 1, 2 Z. Chen, 1 Karen Keppler, 1 Ph. Lerch 2 M. Quack 1, V. Schurig 3 and O. Trapp 4 1 Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland 2 Swiss Light Source, Paul-Scherrer-Institute, CH-5332 Villigen, Switzerland 3 Institute of Organic Chemistry, University of Tubingen, Germany 4 Department of Chemistry, Ludwig Maximilians University, Munich, Germany 72 nd ISMS 2017 WA 01 | 19 -23 June 2017 | 1

Oxirane (ethylene oxide) § A highly strained three-membered heterocycle § Isomeric of acetaldehyde and vinyl alcohol § Determination of abundance can shed light on construction/destruction pathways towards the formation of more complex organic molecules § Observed in the ISM towards Sgr B 2 (J. E, Dickens, W. M. Irvine, M. Ohishi, M. Ikeda, S. Ishikawa, A. Nummelin and Å. Hjalmarson, Astrophys. J. 489, 753757 (1997)) § Observation of deuterated species provides D/H ratio as an indicator of history of the cold prestellar phase in star-forming regions § ~10% or above [XD]/[XH] is commonly found 72 nd ISMS 2017 WA 01 | 19 -23 June 2017 | 2

mono-deuterated oxirane: isotopically chiral see M. Quack, Angew. Chem. Int. Ed. Engl. 28 (1989) 571 for isotopic chirality For isotopic chirality and molecular parity violation see: R. Berger, G. Laubender, M. Quack, A. Sieben, J. Stohner and M. Willeke, Angew. Chem. Int. Ed. Engl. 44 (2005) 3623 72 nd ISMS 2017 WA 01 | 19 -23 June 2017 | 3

Parity violation: Energy difference in enantiomers of a chiral mono-deuterated oxirane molecule Traditional theory: Today: electroweak parity violation exactly by symmetry R S Example : CHBr. Cl. F M. Quack and J. Stohner, Phys. Rev. Lett. 84, 3807 -3810 (2000) 72 nd ISMS 2017 WA 01 | 19 -23 June 2017 | 4

Spectroscopy of 1 -d oxirane § MW: 20 transitions up to 45 GHz, Hirose, C. Bull. Chem. Soc. Jap. , 47, 13111318 (1974) § Theoretical calculation of spectroscopic parameters, C. Puzzarini, M. Biczysko, J. Bloino and Vincenzo Barone. Ap. J, 785, 107 (2014). § Aims: 1) to extend the measurement of pure rotational transitions to the GHz and THz regions to support astronomical observations; 2) further investigation of rovibrational levels based on this ground state study 72 nd ISMS 2017 WA 01 | 19 -23 June 2017 | 5

GHz setup at ETH Zürich Detector 2. 5 m gaseous cell Lock-in amplifier Second-harmonic lock-in detection M. Suter and M. Quack, Appl. Opt. 54, 4417 -4431 (2015) Frequency multiplier 75 -110 GHz MW synthesizer 250 k. Hz-20 GHz 72 nd ISMS 2017 WA 01 | 19 -23 June 2017 | 6

Overview spectra: 69 -113 GHz 25 μbar 294 K GHz 72 nd ISMS 2017 WA 01 | 19 -23 June 2017 | 7

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Spectroscopic parameters of the ground state of 1 d-oxirane Previous MW 1 GHz this study A /MHz 24252. 47(17) 24252. 64843(23) B /MHz 19905. 34(17) 19905. 52198(19) C /MHz 13327. 40(17) 13327. 58408(16) ΔJ /k. Hz 17. 01001(37) ΔK /k. Hz 25. 44301(72) ΔJK /k. Hz 17. 31528(86) δj /k. Hz 13. 17077(19) δk /k. Hz 4. 74440(16) drms / k. Hz 30 N 20 112 1 Hirose, C. Bull. Chem. Soc. Jap. , 47, 1311 -1318 (1974). 72 nd ISMS 2017 WA 01 | 19 -23 June 2017 | 11

Synchrotron-based high resolution FTIR setup at the Swiss Light Source unapodized instrument resolution of 0. 00053 cm-1 (16 MHz) S. Albert, K. K. Albert, Ph. Lerch, M. Quack, Faraday Discussions, 150, 71 -99 (2011) S. Albert, K. K. Albert and M. Quack, High Resolution Fourier Transform Infrared Spectroscopy, in Handbook of High-Resolution Spectroscopy, Vol. 2 (Eds. M. Quack and F. Merkt), John Wiley & Sons, Ltd, Chichester, pp. 965 -1019 (2011) 72 nd ISMS 2017 WA 01 | 19 -23 June 2017 | 12 S. Albert, Ph. Lerch and M. Quack, Chem. Phys. Chem. 14, 3204 -3208 (2013)

Overview spectra: 25 -80 cm-1 (0. 75 -2. 4 THz) 72 nd ISMS 2017 WA 01 | 19 -23 June 2017 | 13

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Impurities in the sample 72 nd ISMS 2017 WA 01 | 19 -23 June 2017 | 16

Impurities in the sample 72 nd ISMS 2017 WA 01 | 19 -23 June 2017 | 17

Spectroscopic parameters of the ground state of 1 d-oxirane Watson’s A-reduction, Ir-representation A / cm-1 B / cm-1 C / cm-1 ΔJ / 10 -6 cm-1 ΔK / 10 -6 cm-1 ΔJK / 10 -6 cm-1 δj / 10 -6 cm-1 δk / 10 -6 cm-1 HJ / 10 -12 cm-1 HJK / 10 -12 cm-1 HKJ / 10 -12 cm-1 HK / 10 -12 cm-1 h. JK / 10 -12 cm-1 h. K / 10 -12 cm-1 drms / cm-1 No. of distinct 1 Included MW 1, GHz 0. 8089812473 0. 663976719 0. 444560261 0. 5715(84) 0. 8468(15) 0. 5798(17) 0. 15857(21) 0. 4382(11) 0. 0000035 132 MW, GHz, THz 0. 808981247 0. 663976719 0. 444560261 0. 56976 (26) 0. 84866 (82) 0. 57729 (95) 0. 15835 (10) 0. 44029 (67) 0. 52 (19) 4. 9 (11) -25. 7 (41) 24. 9 (31) 0. 140 (81) 1. 39 (64) 1. 18 (25) 0. 000074 530 CCSD(T)/cc-p. VTZb 0. 810323354 0. 664053797 0. 444974269 0. 51125 0. 56639 0. 70275 0. 1349 0. 51125 0. 54 5. 3937 -27. 3523 24. 0967 0. 063 2. 56 1. 69 20 MW transitions from Hirose, C. Bull. Chem. Soc. Jap. , 47, 1311 -1318 (1974). 2 C. Puzzarini, M. Biczysko, J. Bloino and Vincenzo Barone. Ap. J, 785, 107 (2014). 3 Values without parenthesis were held fixed to the respective values of the ground state obtained by fitting only transitions in the GHz region of this study. 72 nd ISMS 2017 WA 01 | 19 -23 June 2017 | 18

Comparison between experiment and theory 72 nd ISMS 2017 WA 01 | 19 -23 June 2017 | 19

Conclusion 1 d-oxirane has been measured in both GHz (79 -113 GHz) and THz (0. 75 -2. 4 Hz) regions The analysis of the pure rotational spectra is a success, allowing improved predictions for observation missions Future work The rovibrational spectra of the lowest vibrational modes have been measured, the analysis is in part completed and in part still in progress. 72 nd ISMS 2017 WA 01 | 19 -23 June 2017 | 20

Acknowledgement § The group of Martin Quack at ETH Zürich: www. ir. ETHz. ch 72 nd ISMS 2017 WA 01 | 19 -23 June 2017 | 21