1. O 1 2 2-cyclohexen-1-one (2CHO)

2. Solution-Phase Photochemistry h O OO

3. h S 1 (n,  *) T 1,2 → products O h O OO S0S0

4. Solution-Phase Photochemistry h S 1 (n,  *) T 1,2 → products O h O OO S0S0

5. Solution-Phase Photochemistry h h O OO S 1 (n,  *) T 1,2 → products S 0 → T 1 (n,  *) via CRD Spectroscopy S0S0

6. Solution-Phase Photochemistry h h O OO S 1 (n,  *) T 1,2 → products S 0 → T 1 (n,  *) via CRD Spectroscopy S0S0 ~S 2 ( ,  *)

7. CC C O CC C O n ** T 1 (n,  *) C C C C C C  

8. S0S0 S 1 (n,  *) 385 nm T 1 (n,  *) 407 nm 1500 cm -1

9. Dye Laser Telescope Ringdown Cell PMT Fast A/D Card CRD Spectrum Nd:YAG Laser 10 Hz 355 nm 407 nm, 2-5 mJ/pulse 100  fitter photon loss exp (-kt )

10. 1 Photon loss per pass (parts per thousand)

11. 1 122 99 Absorption

12. 1 39 0 1 39 0 2 000000 39 2 0 39 3 0 39 1 0 122 99 Absorption

13. 1 39 0 1 39 0 2 000000 39 2 0 39 3 0 39 1 0 122 99 39 (?) Absorption

14. 1 0.1 Torr 1.6 Torr 0.3 Torr

22. 94.5 cm -1 99.6 cm -1 39 1 0 T 1 (n,  *)  S 0 0 0 0 (?)

23. 7 cm -1 12 cm -1 94.5 cm -1 99.6 cm -1 T 1 (n,  *)  S 0

24. 94.5 cm -1 99.6 cm -1 000000 39 0 1 T 1 (n,  *)  S 0

25. 99.6 cm -1 94.5 cm -1 98.6 cm -1 93.7 cm -1 39 0 1 000000 39 1 0 T 1 (n,  *)  S 0

26. 99.6 cm -1 94.5 cm -1 98.6 cm -1 93.7 cm -1 39 0 1 39 1 0 000000 T 1 (n,  *)  S 0

27. 99.6 cm -1 98.6 cm -1 94.5 cm -1 93.7 cm -1 000000 39 0 1 39 1 0

28. 99.6 cm -1 98.6 cm -1 94.5 cm -1 93.7 cm -1 000000 39 0 1 39 1 0

29. 34 0 1 38 1 0 39 0 1 39 0 2 99.6 + 98.4 = 198.0 cm -1 94.5 + 93.6 = 188.1 cm -1

30. 98.4 cm -1 99.6 cm -1 000000 39 0 1 39 0 2

31. 98.4 cm -1 99.6 cm -1 262.2 cm -1 000000 39 0 1 38 0 1 39 0 2

32. 38 0 1 98.4 cm -1 99.6 cm -1 000000 39 0 1 39 0 2 38 (?) 262.2 cm -1 S 0 : 248.1 cm -1

33. 98.4 cm -1 99.6 cm -1 262.2  14.1 = 248.1 cm -1 = 38  000000 39 0 1 38 0 1 38 1 1 39 0 2

34. 98.4 cm -1 99.6 cm -1 262.2  14.1 = 248.1 cm -1 = 38  000000 39 0 1 38 0 1 38 1 1 38 1 1 39 0 1 39 0 2 99.3 cm -1

35. 000000 39 0 1 38 0 1 39 0 2 93.6 cm -1 94.5 cm -1 244.6  11.9 = 232.7 cm -1 = 38  38 1 1 38 1 1 39 0 1 94.3 cm -1

36. 345.4 cm -1 000000 34 0 1 38 0 1 262.2 cm -1 99.6 cm -1 39 0 1 215.5 cm -1 37 0 1 C=C twist C=O ip wag

37. 345.4 cm -1 34 0 1 C=O ip wag 34 0 1 38 1 0 39 0 1 34 0 1 37 1 0 39 0 1 34 0 1 37 1 0 34 1 1 39 0 2 99.6 cm -1 98.4 cm -1 000000

38. Fundamental Frequencies (cm -1 )  38 37 C=C twist 34 C=O wag S0S0 99.0 248.1 304.1 485 S 1 (n,  *) 122.1 251.9 303.3 343.9 T 1 (n,  *) 99.6 262.2 215.5 345.4

39. Acknowledgements NSF-RUI (CHE-0848615) Henry Dreyfus Teacher-Scholar Award UW-Eau Claire Office of Research and Sponsored Programs