O
1 2 2-cyclohexen-1-one(2CHO)
Solution-Phase Photochemistry
hnO
OO
Solution-Phase Photochemistry
hnS1(n,p*) T1,2 → products
O
hnO
OO
S0
Solution-Phase Photochemistry
hnS1(n,p*) T1,2 → products
O
hnO
OO
S0
Solution-Phase Photochemistry
hn
hnO
OO
S1(n,p*) T1,2 → products
S0 → T1(n,p*) via CRD Spectroscopy
S0
Solution-Phase Photochemistry
hn
hnO
OO
S1(n,p*) T1,2 → products
S0 → T1(n,p*) via CRD Spectroscopy
S0
~S2(p,p*)
C C
C O
C C
C O n
p*
T1(n,p*)
C
C
C
C
C
C
p
p
S0
S1(n,p*)
385 nm
T1(n,p*)
407 nm
1500 cm-1
Dye Laser
Telescope
Ringdown CellPMT
Fast A/D Card
CRDSpectrum
Nd:YAG Laser10 Hz
355 nm407 nm,
2-5 mJ/pulse
100 W
fitter
phot
on lo
ss
l
exp (-kt )
1
-1500 -1000 -500 00.0
2.0
4.0
6.0
8.0
Wavenumber (cm-1) relative to S S0 origin band
410 400 390 380Photon loss per pass (parts per thousand)
Wavelength (nm)
Phot
on lo
ss p
er p
ass
(par
ts p
er th
ousa
nd)
-1500 -1000 -500 0
Wavenumber (cm-1) relative to S S0 origin band1
122
99
Abs
orpt
ion
-1500 -1000 -500 0
Wavenumber (cm-1) relative to S S0 origin band1
3901 390
2000
3920
3930 391
0
122
99
Abs
orpt
ion
-1500 -1000 -500 0
Wavenumber (cm-1) relative to S S0 origin band1
3901 390
2000
3920
3930 391
0
122
99
2
1
6
3
5444
65
1
3 2
n39 (?)
Abs
orpt
ion
-1500 -1000 -500 00.0
2.0
4.0
6.0
8.0
Pho
ton
loss
per
pas
s (p
arts
per
thou
sand
)
Wavenumber (cm-1) relative to S S0 origin band
410 400 390 380
Wavelength (nm)
1
0.1 Torr
1.6 Torr
0.3 Torr
0
200
400
600
800
1000
1200
Phot
on lo
ss p
er p
ass
(ppm
)24500 24750 25000 25250
Wavenumber (cm-1)
-1800 -1600 -1400 -1200 -1000 -800
Wavenumber (cm-1) relative to S1 S0 origin band
0
200
400
600
800
1000
1200
Phot
on lo
ss p
er p
ass
(ppm
)24500 24750 25000 25250
Wavenumber (cm-1)
-1800 -1600 -1400 -1200 -1000 -800
Wavenumber (cm-1) relative to S1 S0 origin band
200
400
Phot
on lo
ss p
er p
ass
(ppm
)24400 24600 24800
0.02
0.04
0.06
0.08
Wavenumber (cm-1)
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
-1600 -1500 -1400 -1300 -1200
Wavenumber (cm-1) relative to S1 S0 origin band
200
400
Phot
on lo
ss p
er p
ass
(ppm
)24400 24600 24800
0.02
0.04
0.06
0.08
Wavenumber (cm-1)
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
-1600 -1500 -1400 -1300 -1200
Wavenumber (cm-1) relative to S1 S0 origin band
200
400
Phot
on lo
ss p
er p
ass
(ppm
)24400 24600 24800
0.02
0.04
0.06
0.08
Wavenumber (cm-1)
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
-1600 -1500 -1400 -1300 -1200
Wavenumber (cm-1) relative to S1 S0 origin band
DD
OD
O
200
400
Phot
on lo
ss p
er p
ass
(ppm
)24500 24600 24700
0.02
0.04
0.06
Wavenumber (cm-1)
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
-1500 -1400
Wavenumber (cm-1) relative to S1 S0 origin band
DD
OD
O
200
400
Phot
on lo
ss p
er p
ass
(ppm
)24500 24600 24700
0.02
0.04
0.06
Wavenumber (cm-1)
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
-1500 -1400
Wavenumber (cm-1) relative to S1 S0 origin band
DD
OD
O
200
400
Phot
on lo
ss p
er p
ass
(ppm
)24500 24600 24700
0.02
0.04
0.06
Wavenumber (cm-1)
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
-1550 -1500 -1450 -1400 -1350
Wavenumber (cm-1) relative to S1 S0 origin band
94.5 cm-1
99.6 cm-1
DD
OD
O
3910
T1(n,p*) S0
000 (?)
7 cm-1
12 cm-1
200
400
Phot
on lo
ss p
er p
ass
(ppm
)24500 24600 24700
0.02
0.04
0.06
Wavenumber (cm-1)
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
-1550 -1500 -1450 -1400 -1350
Wavenumber (cm-1) relative to S1 S0 origin band
94.5 cm-1
99.6 cm-1
DD
OD
O
T1(n,p*) S0
200
400
Phot
on lo
ss p
er p
ass
(ppm
)24500 24600 24700
0.02
0.04
0.06
Wavenumber (cm-1)
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
-1550 -1500 -1450 -1400 -1350
Wavenumber (cm-1) relative to S1 S0 origin band
94.5 cm-1
99.6 cm-1
DD
OD
O
000
3901
T1(n,p*) S0
200
400Ph
oton
loss
per
pas
s (p
pm)
24500 24600
0.02
0.04
0.06
Wavenumber (cm-1)
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
-1600 -1500
Wavenumber (cm-1) relative to S1 S0 origin band
DD
OD
99.6 cm-1
94.5 cm-1
98.6 cm-1
93.7 cm-1
3901
O
000
3910
T1(n,p*) S0
200
400
Phot
on lo
ss p
er p
ass
(ppm
)24400 24600 24800
0.02
0.04
0.06
0.08
Wavenumber (cm-1)
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
-1600 -1500 -1400 -1300 -1200
Wavenumber (cm-1) relative to S1 S0 origin band
DD
OD
99.6 cm-1
94.5 cm-1
98.6 cm-1
93.7 cm-1 3901
3910
O
000
T1(n,p*) S0
200
400
Phot
on lo
ss p
er p
ass
(ppm
)
0.02
0.04
0.06
0.08
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
-100 0 100 200 300
Wavenumber (cm-1) relative to T1 S0 origin band
DD
OD
99.6 cm-1
98.6 cm-1
94.5 cm-1
93.7 cm-1
O
000
3901
3910
200
400
Phot
on lo
ss p
er p
ass
(ppm
)
0.02
0.04
0.06
0.08
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
-100 0 100 200 300
Wavenumber (cm-1) relative to T1 S0 origin band
DD
OD
99.6 cm-1
98.6 cm-1
94.5 cm-1
93.7 cm-1
O
000
3901
3910
300
350
400
450
500
550Ph
oton
loss
per
pas
s (p
pm)
0.05
0.06
0.07
0.08
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
170 180 190 200 210
Wavenumber (cm-1) relative to T1 S0 origin band
DD
OD
O
3401 381
0 3901
3902
99.6 + 98.4 = 198.0 cm-1
94.5 + 93.6 = 188.1 cm-1
200
400Ph
oton
loss
per
pas
s (p
pm)
0.04
0.06
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
0 100 200
Wavenumber (cm-1) relative to T1 S0 origin band
98.4 cm-1
99.6 cm-1
O00
0
3901
3902
200
400Ph
oton
loss
per
pas
s (p
pm)
0.04
0.06
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
0 100 200
Wavenumber (cm-1) relative to T1 S0 origin band
98.4 cm-1
99.6 cm-1
262.2 cm-1
O00
0
3901
3801
3902
200
400Ph
oton
loss
per
pas
s (p
pm)
0.04
0.06
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
0 100 200
Wavenumber (cm-1) relative to T1 S0 origin band
O
3801
98.4 cm-1
99.6 cm-1
000
3901
3902
n38 (?)
262.2 cm-12
1
6
3
5444
65
1
3 2
S0: 248.1 cm-1
200
400Ph
oton
loss
per
pas
s (p
pm)
0.04
0.06
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
0 100 200
Wavenumber (cm-1) relative to T1 S0 origin band
98.4 cm-1
99.6 cm-1
262.214.1 = 248.1 cm-1 = n38
O00
0
3901
3801381
1
3902
200
400Ph
oton
loss
per
pas
s (p
pm)
0.04
0.06
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
0 100 200
Wavenumber (cm-1) relative to T1 S0 origin band
98.4 cm-1
99.6 cm-1
262.214.1 = 248.1 cm-1 = n38
O00
0
3901
3801381
1 3811390
1
3902
99.3 cm-1
200
400
600
Phot
on lo
ss p
er p
ass
(ppm
)
0.04
0.06
0.08
0.10
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
0 100 200
Wavenumber (cm-1) relative to T1 S0 origin band
DD
OD00
0
3901
3801
3902
93.6 cm-1
94.5 cm-1
244.611.9 = 232.7 cm-1 = n38
3811 381
13901
94.3 cm-1
200
400
Phot
on lo
ss p
er p
ass
(ppm
)
0.04
0.06
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
0 100 200 300
Wavenumber (cm-1) relative to T1 S0 origin band
345.4 cm-1
O
000
3401
3801
262.2 cm-1
99.6 cm-1
3901
215.5 cm-1
3701
C=Ctwist
C=Oip wag
200
400
Phot
on lo
ss p
er p
ass
(ppm
)
0.04
0.06
Extin
ctio
n co
effic
ient
(M
-1 c
m-1)
0 100 200 300
Wavenumber (cm-1) relative to T1 S0 origin band
345.4 cm-1
O
3401
C=Oip wag
3401 381
0 3901
3401 371
0 3901
3401 371
0
3411 390
2
99.6 cm-1
98.4 cm-1
000
Fundamental Frequencies (cm-1)
n39
n38
n37 C=C twist
n34 C=O wag
S0
99.0
248.1
304.1
485
S1(n,p*)
122.1
251.9
303.3
343.9
T1(n,p*)
99.6
262.2
215.5
345.4
Acknowledgements
• NSF-RUI (CHE-0848615)
• Henry Dreyfus Teacher-Scholar Award
• UW-Eau Claire Office of Research and Sponsored Programs