1. Time-Resolved FTIR Emission Spectroscopy of the (v 1 )-CH Stretch of the Ketenyl (HCCO) Radical Michael J. Wilhelm, William McNavage, and Raymond Groller Department of Chemistry, University of Pennsylvania Hai-Lung Dai Department of Chemistry, Temple University 62 nd International Symposium on Molecular Spectroscopy [RF03] : Thursday, June 21, 2007

2. All Roads Lead to Ketenyl… HCCH + … NO 2 + UV  NO + O( 3 P) HCCH + O( 3 P)  HCCO + H HCCO + O 2  H + CO + CO 2 combustion atmospheric

3. Past Spectroscopic Studies of Ketenyl: K.G. Unfried, G.P. Glass, and R.F. Curl, Chem. Phys. Lett., 117, 33 (1991) Vibrational Spectroscopy Infrared Flask Kinetic Spectroscopy (v 2 ) Asymmetric CCO Stretch: (v 2 ) Asymmetric CCO Stretch: Pure Rotational Spectrum of HCCO with Sub-millimeter Wave Spectroscopy: Large (Ka)-dependency  Renner-Teller Interaction Near-Prolate Symmetric Top Y. Endo and E. Hirota, J. Chem. Phys., 8, 4319 (1991) Electronic Spectroscopy of the B  X System of HCCO: LIF - Origin of the (B)-State PFY – (v 6 ) CCH Bend Small fluorescence quantum yield.. LIF not advisable! Osborn, Mordaunt, Choi, Bise, Neumark and Rohlfing, J. Chem. Phys., 106, 10087 (1997) Brock, Mischler, and Rohlfing, J. Chem. Phys., 110, 6773 (1999) M.J. Krish, J.L. Miller, and L.J. Butler, J. Chem. Phys., 119, 176 (2003) Generation of Ketenyl..

4. Collider Gas Input [2-10 Torr] Sample Input [10 – 100 mTorr] Oscilloscope Bruker Transient Recorder Board Pad82a MM IFS 66s Time-Resolved Fourier Transform Infrared Emission Spectroscopy (TR FTIRES): ArF Excimer : LPX 200 {l = 193 nm, 20 Hz, ≤ 100 mJ/pulse} Pre-Amp + Amplifier Win2K PC / OPUS f1f2 Photodiode trigger Gas Cell To Glass Manifold / Mechanical Pump (i.e.  Continuous Flow..) Capacitance Manometer [0-10 Torr] Step-Scan RA + h 193.3 nm  R ‡ + A ‡ R ‡ (v’=k) + M  R ‡ (v’=k-1) + M * : R ‡ (v’=1) + M  R (v’=0) + M *

5. HCC-O-CH 2 CH 3 + (193 nm)  HCCO + CH 2 CH 3 Time-Resolved FTIR Emission Spectra: HCCO(v 2 )  CO HCC[X  A] CH 2 CH 3  (?) {HCC(v 1 )  HCCO(v 1 )} -- Early -- Late

6. 2D Cross-Spectral Correlation Analysis: (A) (B) Frequency / cm -1 Intensity / a.u. Time /  s (A) Time /  s Intensity / a.u. Frequency (B) Time /  s Intensity / a.u. Frequency synchronousasynchronous

7. 2D Cross-Spectral Synchronous Correlation Analysis: 16.2  s Time-Resolved Data Set(1) Time-Resolved Data Set(2)

8. 2D Cross-Spectral Synchronous Correlation Analysis: 0.05-1.75  s (0.9  s) 5.15-6.85  s (6.0  s) 10.25-11.95  s (11.1  s) 15.35-17.05  s (16.2  s)

9. Extracted (time-resolved) Synchronous Diagonals: 16.2  s 0.9  s 16.2  s HCCO(v 1 ) HCCH(v 3 ) HCC(v 1 ) PTS + Vibronic MS-TOF

10. 2D Cross-Spectral Asynchronous Correlation Analysis: Time-Resolved Data Set(1) Time-Resolved Data Set(2)

11. 2D Cross-Spectral Asynchronous Correlation Analysis: CO(0  1) HCCO(v 2 )

12. Rotational Contour Simulation: HCCH (v 3 ) HCC (v 1 ) HCCO[v 1 ] ~ 3232 cm -1 Near-Prolate Symmetric Top..

13. IR Spectral Assignments: [X1] – Gaussian03 Calculation [X2] – Peter Szalay (Private Communication)

14. Acknowledgments: U.S. Department of Energy, Basic Energy Sciences NASA Earth System Science Fellowship (WM) Financial Support: People: Hai-Lung Dai (Advisor) Matt Nikow Min Zhang Grazia Gonella Jia Zeng Jianqiang Ma Jun Han Michelle Wang Shi-Hui Jen William McNavage Ray Groller