Rotational Spectra and Structural Determination of HCCNCS Wenhao

Rotational Spectra and Structural Determination of HCCNCS Wenhao Sun, Rebecca Davis, Jennifer van Wijngaarden Department of Chemistry, University of Manitoba, Winnipeg, MB, Canada RF 08 ISMS 72 st Meeting June 22, 2017

[H, N, C, S] Family Similarly, [H, N C, O] family √ √ √ *Energies are calculated at the ae-CCSD(T)/cc-pw. CVQZ and corrected for zero -point vibrational contributions calculated at the fc-CCSD(T)/cc-PV(Q+d)Z level. Brett A. Mc. Guire, et al, Phys. Chem. Phys. , 2016, 18, 22693 S. Brunken, et al, The Astrophys. J. , 2009, 697: 880 -885, 2009 May 20 S. Ross, J. Mol. Spectrosc, 1992, 152 -167 *Energies are calculated at the CCSD(T)/cc-p. CV 5 Z 1

Quantum Monodromy Linear Brenda P. Winnewisser, et al, Phys. Rev. Lett. 2005, 95, 243002 Manfred Winnewisser, et al, J. Mol. Spectrosc. 2006, 798, 1 -26 Nearly bent 2

Potential Energy Curve 2. 00 1. 80 1. 60 ∆E/k. J/mol-1 1. 40 1. 20 1. 00 0. 80 0. 60 0. 40 0. 20 0. 00 150 170 C 3 -N 4 -C 5/º MP 2/cc-p. VQZ 190 210 B 3 LYP/cc-p. VQZ Linear Nearly bent 3

Potential Energy Curve or Linear Nearly bent 4

cp FTMW Spectrometer Experimental conditions: 1. 1% acetylene diluted with Ne + Bubbler (CH 3 NCS, 37℃ ) 2. Acetal Delrin spacers: 5 mm and 8 mm thick; copper electrodes: 5 mm thick; channel diameter: 2. 5 mm 3. High voltage: 700 V. 4. Expansion duration: 750 µs Chirp duration: 4 µs 5. Bandwidth: 1000 MHz 6. 25 FIDs * 16 µs/FID L. Evangelisti, G. Sedo, J. van Wijngaarden, J. Phys. Chem. A, 2011, 115, 685 -690 5

Broadband Microwave Spectra cp spectrum simulation 6

Balle Flygare FTMW Spectrometer Sample Mixing Manifold Microwave Circuit Vacuum Chamber Microwave Source G. Sedo, J. van Wijngaarden, J. Chem. Phys. 2009, 131, 044303. 7

Hyperfine Structure: 14 N Parent- 29 lines Isotopic lines 5 7 HCCNCS-parent 8 16 HCCNCS-34 S J=6 -5 200 cycles 2000 cycles 8

Structural parameters Parent- 29 lines Isotopic lines 5 7 8 16 HCCNCS-re 1. 2937(7) 1. 575 1. 302 1. 210 HCCNCS-r 0 1. 189 1. 2061(2) 1. 5690(6) 1. 1780(10) Equilibrium structures are calculated at CCSD(T)/ cc-p. VQZ, for H, C, N and cc-p. V(Q+d)Z for S. Z. Kisiel, PROSPE-Programs for Rotational Spectroscopy, http: //info. ifpan. edu. pl/~kisiel. htm. 9

Vibrational State C-N-C bending mode: 1Π state (70. 4 cm-1 above ground state at B 3 LYP/cc-p. VQZ) l-type doubling hfs Doppler J=6 -5 10

Why is HCCNCS linear? Linear Bent 11

NBO analysis NBO calculations are calculated at B 3 LYP/cc-p. VQZ. 12

Acknowledgements