1. CHIRPED PULSE AND CAVITY FT MICROWAVE SPECTROSCOPY OF THE HCOOH – N(CH 3 ) 3 WEAKLY BOUND COMPLEX Rebecca B. Mackenzie, Christopher T. Dewberry, and Kenneth R. Leopold Department of Chemistry, University of Minnesota 70 th International Symposium on Molecular Spectroscopy 1

2. Aerosols in the Atmosphere Impact the global energy budget Air quality 2

3. Homogeneous Nucleation Kathmann, S. M.; Schenter, G. K.; Garrett, B. C. Advances in Quantum Chemistry, Elsevier, 55, 429–447 (2008). 3

4. New particle formation in the atmosphere – How do low-MW compounds contribute to particle growth? – Formation of organic salts Amine-Carboxylic Interactions Barsanti, K.C., McMurry, P.H., Smith, J.N. Atmos. Chem. Phys. 9, 2949–2957 (2009). 4 R Evaporation R R (-)(+) Organic Salt

5. 5 Predicted Spectrum a-type spectrum Frequency (MHz) 60009000120001500018000 2.81 D 0.65 D M06-2X/6-311++G(3df,3pd) 1.62 Å 1.03 Å Looking down the x-axis

6. Tandem Cavity/Chirp FTMW 6 Cavity Experiment Chirp Experiment

7. Introduction of sample – 1 % TMA in Ar on pulse-line – HCOOH on continuous flowline Experimental Ar over HCOOH bubbler 1 % TMA in Ar Chirp/Cavity 7

8. 8 Chirp Spectrum Unedited Chirp, 6-18 GHz Remove larger lines from monomers/noise 60009000120001500018000 Predicted Frequency (MHz)

9. 9 Chirp Spectrum 60009000120001500018000 Predicted Edited Chirp, 6-18 GHz Larger lines removed Frequency (MHz)

10. 10 Chirp Spectrum Edited Chirp, 15-18 GHz Larger lines removed Frequency (MHz) 15000 160001700018000 Predicted: J 6←5 Constant Computational (MHz) Experimental (MHz) A3895.0 3826.53(17) B1478.7 1446.37300(34) C1366.6 1334.66883(30)

11. 11 Isotopic Substitution DCOOH added to system TMA 13 C х2 (the degenerate carbon) Seen in natural abundance (one or the other)

12. TMA-HOOCHTMA( 13 Cx2)-HOOCHTMA-HOOCD A (MHz)3826.53(17)3767.74(16)3812.21(15) B (MHz)1446.37300(34)1435.39550(37)1404.23892(51) C (MHz)1334.66883(30)1327.80908(37)1297.05996(28) N χ aa (MHz)-2.8193(29)-2.840(15)-2.906(53) N (χ bb -χ cc ) (MHz)-1.7236(68)-1.536(60)-1.60(14) Δ J (kHz)0.567(11)0.612(14)0.6038(57) Δ JK (kHz)1.86(13)1.536(87)1.861* RMS (kHz)1823 N532219 Spectroscopic Constants 12

13. 13 Structure Analysis 3.3178(12) Å 3.281 Å 1.8345(22) Å 1.807 Å Kraitchman Analysis Computational

14. 14 Structure Analysis R CM Determine R CM from C Angular orientation not determined θ1θ1 θ2θ2 Use Kraitchman distances to help orient the monomers 3.24383 Å

15. 15 Proton Transfer Parameter How much has the proton transferred? TMA H + (a) TMA Q B PT 100% 0% TMA-HCOOH 18% TMA-HNO 3 (c) 31% TMA-HI (b) 58% 9% TMA-H 2 O (d) Using TMA 14 N χ cc to assess proton transfer (a)Domene, C., Fowler, P.W., Legon, A.C. Chem. Phys. Lett. 309, 463-470 (1999) (b)Legon, A.C., Rego, C.A. J. Chem. Phys. 99, 1463-1468 (1993). (c)Sedo, G., Leopold, K.R. J. Phys. Chem. A. 115, 1787-1794 (2011). (d)Tubergen, M. J., Kuczkowski, R.L., J. Am. Chem. Soc. 115, 9263-9266 (1993).

16. HCOOH-TMA 16 Q B PT v. H-Bond Length H + TMA (a) HNO 3 -TMA (c) H 2 O-TMA (d) HI-TMA (b) Theoretical Experimental (a)Domene, C., Fowler, P.W., Legon, A.C. Chem. Phys. Lett. 309, 463-470 (1999) (b)Legon, A.C., Rego, C.A. J. Chem. Phys. 99, 1463-1468 (1993). (c)Sedo, G., Leopold, K.R. J. Phys. Chem. A. 115, 1787-1794 (2011). (d)Tubergen, M. J., Kuczkowski, R.L., J. Am. Chem. Soc. 115, 9263-9266 (1993). H-Bond Length

17. 17 From the Other Perspective… That proton is 18% transferred. How much is that proton transferred?

18. 18 From the Other Perspective… TMA- 31%TMA- 58% Q B PT HNO 3 - 62% Q A PT Q B PT HI- 81% Q A PT TMA-18% Q B PT HCOOH-38-48% Q A PT

19. The spectra for HCOOH-N(CH 3 ) 3, DCOOH-N(CH 3 ) 3, and HCOOH-N( 13 CH 3 )(CH 3 ) 2 were observed Structure analysis is in progress Analysis of hyperfine indicates a hydrogen bonded system, but there’s evidence of some proton transfer Good first step, continue work by looking at the monohydrate of the complex 19 Some Closing Thoughts

20. Funding & Acknowledgements Leopold Group Dr. Chris Dewberry Dr. Pete McMurry 20

21. TMA-HCOOH Complex 21

22. Comparison of Fit 16300 16500 1670016900 17000 22 1730016700

23. Proton Transfer Parameter 23