1. JET-COOLED A-X SPECTRA OF THE β- HYDROXYETHYLPEROXY RADICAL AND ITS ISOTOPOLOGUES Laser Spectroscopy Facility Department of Chemistry The Ohio State University 6/21/2010 MING-WEI CHEN, GABRIEL M. P. JUST *, TERRANCE J. CODD and TERRY A. MILLER ~~ * Current affiliation: Lawrence Berkeley National Laboratory

2. G1G2G3G1G2G3  Importance of the β-HEP has been presented in MI07*.  Conformer assignment on RT spectrum is only on the basis of vibronic analysis.*  Information from the jet- cooled spectrum:  Obtain the rotational constants from the jet-cooled spectrum of the 7381 cm -1 band found in RT CRDS.  Check the geometry from experiment and compare with the ab initio calculation. *See also: R. Chhantyal-Pun, N. D. Kline, P. S. Thomas and T. A. Miller J. Phys. Chem. Lett., 1, 1846 (2010)

3. Or Raman Cell 1st stokes ∼ 1.3 μm ∼ 4 mJ Δν ∼ 200 MHz (limited by pressure broadening in H 2 ) BBO YAG 20 Hz BBO ∼ 1.3 μm ∼ 2mJ Δν ∼ 70 MHz (measured) InGaAs Detector 67 cm 45- 100 mJ / pulse Δν (FWHM) ∼ 7 - 30 MHz (FT limited)

4. IR Beam 9 mm -HV radical densities of 10 12 - 10 13 molecules/cm 3 (10 mm downstream, probed) rotational temperature of 15 - 30 K (residual Δν Doppler ~155MHz at 20K) plasma voltage ~ 500 V, I  1 A (~ 400 mA typical), 100 µs length dc and/or rf discharge, discharge localized between electrode plates, increased signal compared to longitudinal geometry Previous similar slit-jet designs: D.J. Nesbitt group, Chem. Phys. Lett. 258, 207 (1996) R.J. Saykally group, Rev. Sci. Instrum. 67, 410 (1996) T. A. Miller group, Phys. Chem. Chem. Phys. 8, 1682 (2006). 5 cm 5 mm 10 mm Electrode Viton Poppet + O 2

5. Δν spectral ~250MHz (measured with SRS, residual Δν Doppler ~155MHz) NO 3 talk on Wednesday: WJ04

6. Specview simulation (asymmetric top) assuming Δν=250MHz, rotational constants are from MP2(Full)/6-31G* optimized geometry. Jet-cooled experimental data

7. β-HEP S. Wu, P. Rupper, P. Dupré and T. A. Miller, 62 nd International Symposium on Molecular Spectroscopy, RF09 (2007) HD

8.  Band origin shifts.  Better resolved rotational contour. ICH 2 CH 2 OD (Not commercially available) CC H H H H HO I +D 2 O CC H H H H DO I

9.  Isotope shifts observed among four different isotopologues. Confirming four different species observed in the experiments.  Similar overall rotational contours for all four spectra, showing four measured species are having similar structure. β-HEP β-HEP-d4 β-DHEP β-DHEP-d4

10.  Rotational constants and Lorentzian linewidth (Δν L ) are obtained for each isotopologue by evolutionary algorithm. Upper = exp. data Lower = simulation from EA analysis G. M. P. Just, P. Rupper, T. A. Miller and W. L. Meerts J. Chem. Phys., 131, 184303 (2009) G. M. P. Just, P. Rupper, T. A. Miller and W. L. Meerts Phys. Chem. Chem. Phys., 12, 4773 (2010) β-HEP β-HEP-d4 β-DHEP β-DHEP-d4

12.  Natural linewidth ~21 ps~20 ps~46 ps~64 ps Excited state lifetime (τ) of β-HEP : ~20ps Δν L =7442 MHz*Δν L =7878 MHz*Δν L =3469 MHz*Δν L =2472 MHz* *1σ of EA estimated Δν L is ~225MHz

13. 7206cm -1 c) Ground state barrier (+ZPE) a)-d) : 6160-10530 cm -1 a) S. Olivella, A. Solé, J. Phys. Chem. 108, 11651 (2004) b) K. T. Kuwata, T. S. Dibble, E. Sliz, E. B. Peterson, J. Phys. Chem. A, 111, 5032 (2007) c) J. Zádor, R. X. Fernandes, Y. Georgievskii, G. Meloni, C. A. Taatjes, J. A. Miller, Proc. Combustion Inst. 32, 271 (2009) d) Present calculation with B3LYP/CBS/cc-pV5Z level of calculation.

14. First excited state energies calculated by TD DFT/6- 311++G(d,p) 7206cm -1 c) a) S. Olivella, A. Solé, J. Phys. Chem. 108, 11651 (2004) b) K. T. Kuwata, T. S. Dibble, E. Sliz, E. B. Peterson, J. Phys. Chem. A, 111, 5032 (2007) c) J. Zádor, R. X. Fernandes, Y. Georgievskii, G. Meloni, C. A. Taatjes, J. A. Miller, Proc. Combustion Inst. 32, 271 (2009) d) Present calculation with B3LYP/CBS/cc-pV5Z level of calculation. Ground state barrier (+ZPE) a)-d) : 6160-10530 cm -1

15. First excited state energies calculated by TD DFT/6- 311++G(d,p), shifted to match the A-X experimental excitation energy of β-HEP. ~~ 7206cm -1 c) a) S. Olivella, A. Solé, J. Phys. Chem. 108, 11651 (2004) b) K. T. Kuwata, T. S. Dibble, E. Sliz, E. B. Peterson, J. Phys. Chem. A, 111, 5032 (2007) c) J. Zádor, R. X. Fernandes, Y. Georgievskii, G. Meloni, C. A. Taatjes, J. A. Miller, Proc. Combustion Inst. 32, 271 (2009) d) Present calculation with B3LYP/CBS/cc-pV5Z level of calculation. e) Present jet-cooled data. f) See TG14. Ground state barrier (+ZPE) a)-d) : 6160-10530 cm -1 ~7389 cm -1 e) ΔE ethoxy ~355 cm -1 f)

16. First excited state energies calculated by TD DFT/6- 311++G(d,p), shifted to match the A-X experimental excitation energy of β-HEP. ~~ 7206cm -1 c) a) S. Olivella, A. Solé, J. Phys. Chem. 108, 11651 (2004) b) K. T. Kuwata, T. S. Dibble, E. Sliz, E. B. Peterson, J. Phys. Chem. A, 111, 5032 (2007) c) J. Zádor, R. X. Fernandes, Y. Georgievskii, G. Meloni, C. A. Taatjes, J. A. Miller, Proc. Combustion Inst. 32, 271 (2009) d) Present calculation with B3LYP/CBS/cc-pV5Z level of calculation. e) Present jet-cooled data. f) See TG14. Ground state barrier (+ZPE) a)-d) : 6160-10530 cm -1 ~7389 cm -1 e) ΔE ethoxy ~355 cm -1 f)

17. First excited state energies calculated by TD DFT/6- 311++G(d,p), shifted to match the A-X experimental excitation energy of β-HEP. ~~ 7206cm -1 c) a) S. Olivella, A. Solé, J. Phys. Chem. 108, 11651 (2004) b) K. T. Kuwata, T. S. Dibble, E. Sliz, E. B. Peterson, J. Phys. Chem. A, 111, 5032 (2007) c) J. Zádor, R. X. Fernandes, Y. Georgievskii, G. Meloni, C. A. Taatjes, J. A. Miller, Proc. Combustion Inst. 32, 271 (2009) d) Present calculation with B3LYP/CBS/cc-pV5Z level of calculation. e) Present jet-cooled data. f) See TG14. Ground state barrier (+ZPE) a)-d) : 6160-10530 cm -1 ~7389 cm -1 e) I.C. ΔE ethoxy ~355 cm -1 f)

18. First excited state energies calculated by TD DFT/6- 311++G(d,p), shifted to match the A-X experimental excitation energy of β-HEP. ~~ 7206cm -1 c) a) S. Olivella, A. Solé, J. Phys. Chem. 108, 11651 (2004) b) K. T. Kuwata, T. S. Dibble, E. Sliz, E. B. Peterson, J. Phys. Chem. A, 111, 5032 (2007) c) J. Zádor, R. X. Fernandes, Y. Georgievskii, G. Meloni, C. A. Taatjes, J. A. Miller, Proc. Combustion Inst. 32, 271 (2009) d) Present calculation with B3LYP/CBS/cc-pV5Z level of calculation. e) Present jet-cooled data. f) See TG14. Ground state barrier (+ZPE) a)-d) : 6160-10530 cm -1 ~7389 cm -1 e) ΔE ethoxy ~355 cm -1 f) I.C.

19.  Conclusions: Jet-cooled CRD origin band spectra of HEP G 1 G 2 G 3 conformer and other three isotopologues are successfully obtained and analyzed with evolutionary algorithm. Unusual lifetime broadening of spectra are measured and isotope effect are strongly correlated to the intramolecular hydrogen migration from the OH to the OO sites.  Future works: Clarify the mechanism, with the assistance of higher level ab initio calculation. A newly opened application of jet-cooled HRCRDS and EA to characterize the hydrogen migration of radicals.

20. The Miller Group (OSU): Dr. Miller Dmitry Melnik (MI13) Phillip Thomas (MI04) Jinjun Liu (TG14) Rabi Chhantyal-Pun (MI07) Terrance Codd Neal Kline Funding: NSF DOE Your attention! Dr. Meerts (EA and computer resource) NO 3 talk on Wednesday: WJ04 National Taiwan University: Pei-Nung Chen (discussion of synthesis)

21. S. Sawada and T. Totsuka, Atmos. Environ. 20, 821 (1986) J. Zádor, R. X. Fernandes, Y. Georgievskii, G. Meloni, C. A. Taatjes, J. A. Miller, Proc. Combustion Inst. 32, 271 (2009) Ethylene emission ~18-45  10 6 T/year ~10 -12 cm 3 molecule -1 s -1 10 6 faster then O 3 rxn! ~10 -11 cm 3 molecule -1 s -1 β-HydroxyEthylPeroxy

22. Nd:YAG (20Hz) Diode laser (CW) Ti:Sa Ring (CW) PZT Driver PD OC BD λ/2 BS P Ti:Sa OI P. Dupre and T. A. Miller, Rev. Sci. Inst., 78, 033102 (2007) 45- 100 mJ / pulse Δν (FWHM) ∼ 7 - 30 MHz (FT limited)

23. W. L. Meerts, M. Schmitt, Int. Rev. Phys. Chem. 25, 353 (2006) Initialization Evaluation Selection Stop Reproduction Mutation Yes No Representation of parameters, value of parameters are chosen by user within the upper and lower limit. Solutions with varied parameters are generated randomly to form a population. No prior knowledge is necessary. Solutions are evaluated by the fitness function (cost function), measuring the quality of each solution. User defined termination point, process will be continued if not terminated. Pairs of solutions are selected for reproduction to explore the error landscape. Cost surface is explored by mutation process for the best solutions.

24. +0.4 ppm G. M. P. Just, P. Rupper, T. A. Miller and W. L. Meerts J. Chem. Phys., 131, 184303 (2009)

25. ICD 2 CD 2 OH ICD 2 CD 2 OD $229. 00 / 5g $412. 50 / 500mg Not commercially available (One complete scan requires 12-15 g of 2-iodoethanol)