Carlos E. Crespo-Hernández, Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106
Photochemistry of Environmentally Relevant Nitro-Polycyclic Aromatic Hydrocarbons 10
Time delay (ps) 0.00 0.33 0.45 0.57 0.80
5
20 15
20 10
0 30
1NN -3
2M1NN
Time delay (ps) 0.00 0.30 0.43 0.60 0.73 0.90
5
0 350
10
400
450
500
550
600
Time delay (ps) 0.00 0.20 0.33 0.47 0.63 0.87
5
0 350
650
400
450
Wavelength (nm)
Cyclohexane
10 5
20
600
650
Time delay (ps) 0.8 1.6 2.9 6.2 14 31
Acetonitrile
2NN
10
Time delay (ps) 0.8 2.5 8.0 15 30 85
1NN
Time delay (ps) 0.9 1.8 4.4 12 25 49
2M1NN
0 30
Time delay (ps) 0.8 1.4 2.7 4.9 9.4 16 37 75
20 10
1NN
0
0 8 6 4
Time delay (ps) 0.9 1.3 2.4 5.3 12 24
6 4
2M1NN
2
2 400
450
500
Wavelength (nm)
1NN
550
20
10
0 350
30
-3
30
2NN
ΔA (10 )
-3
ΔA (10 )
0 40
500
2M1NN
Wavelength (nm)
Time delay (ps) 0.8 1.5 2.5 4.3 11 35
15
2NN
1NN
Time delay (ps) 0.00 0.25 0.40 0.53 0.63 0.80
20
0
0
20
Acetonitrile
5
Time delay (ps) 0.00 0.30 0.40 0.50 0.60 0.70 0.80
30
2NN
Time delay (ps) 0.00 0.20 0.33 0.47 0.64 0.77
10
ΔA (10 )
-3
ΔA (10 )
0 40
2NN Cyclohexane
2M1NN
550
600
650
0 350
400
450
500
550
600
650
Wavelength (nm)
Nitro-polycyclic aromatic hydrocarbons have been identified as persistent organic pollutants that undergo sunlight-induced degradation in the environment. Our group has developed laboratory models that enable quantitative measurements of high-energy electronic states and reactive species that ultimate lead to chemical transformation of these pollutants. It has been shown that the orientation of the nitro group modulates the probability of forming these reactive species and their subsequent chemistry.
