Study of the CH2I + O2 Reaction with a Step-scan Fourier-transform Infrared Absorption Spectrometer:
Spectra of the Criegee Intermediate CH2OO and Dioxirane(?)
1
Yu-Hsuan Huang1 and Yuan-Pern Lee1, 2
1 Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Taiwan
2 Institute of Atomic and Molecular Sciences, Academia Sinica, Taiwan
69th International Symposium on Molecular Spectroscopy
2
Importance of CH2OOCriegee mechanism important for the removal of unsaturated hydrocarbons and for the production of OH in the atmosphere R. Criegee, Rec. Chem. Prog. 18, 111 (1957)
++
Decomposition of CH2OO
Chen et al., J. Phys. Chem. A 106, 1877 (2002)
(kcal/mol-1)
stabilizationIsomerization and decomposition
HCOOH, OH, CH3,
CO, CO2, etc
(primary ozonide)
(Criegee intermediate)
Simplest Criegee internediate:CH2OO
3
Experimental observation of CH2OOPhotoionization mass spectrometry
Taatjes et al, J. Am. Chem. Soc. 130, 11883 (2008)Welz et al, Science 335, 204 (2012)
• CH2I + O2 CH2OO + I
Huang et al., J. Phys. Chem. Lett 3, 3399 (2012)Stone et al. Phys. Chem. Chem. Phys. 15, 19119 (2013)
Proposed mechanism
CH2I + O2 → CH2IOO*CH2OO + I
CH2IOOM
0
1
0
1
0
2
0
2
0
2
1500 1400 1300 1200 1100 1000 900 800
0
2
IR In
teni
sity
/arb
. uni
tA
bsor
bacn
e /1
0-2
Wavenumber /cm-1
(f) cis-CH2IOO
(e) methylenebis(oxy)
(d) dioxirane
(c) CH2OO
(b) expt. 0-12.5s
(a) CH2I2
4
IR Identification of CH2OOComparison of observed spectrum with simulated spectrum (1 cm-1)
Su et al., Science 340, 174 (2013)
5
Experimental setup
6Absorption spectrum at 0.25 cm-1 resolution
0
2
4
6
1450 1400 1350 1300 1250 1200 950 900 850 800
0
2
4
6
A
bsor
banc
e / 1
0-
Wavenumber / cm-
0-12.5 μs
0-25 μs
1 cm-1
0.25 cm-1
CH2I2/N2/O2 (0.13/2.77/97.12)@248 nm, Pt = 94 torr
ν8
ν6ν4
ν3 ν5
Su et al., Science 340, 174 (2013)
7Spectral analysis: near prolate approximation a
b
c
κ = -1 prolateκ = +1 oblate
for CH2OO
Parallel transitions
𝐹 (𝜐 , 𝐽 ,𝐾 )=𝜈𝜐+(𝐴¿¿𝜐−~𝐵𝜐)𝐾 2+~𝐵𝜐 𝐽 ( 𝐽+1 ) ¿
~𝑩𝝊=(𝑩𝝊+𝑪𝝊)
𝟐
Perpendicular transitions
𝜈 𝐽 ,𝐾=𝜈0+ [ Δ 𝐴− Δ~𝐵 ] 𝐾2+∆~𝐵 𝐽 ( 𝐽+1 )
𝜈 𝐽 ,𝐾=𝜈0+ [ Δ 𝐴− Δ~𝐵 ] 𝐾2+(∆~𝐵 𝐽+2~𝐵′ ) ( 𝐽+1 )
ΔJ = 0, Q branch
ΔJ = 1, R branch
ΔJ = -1, P branch 𝜈 𝐽 ,𝐾=𝜈0+ [ Δ 𝐴− Δ~𝐵 ] 𝐾2+¿
,
𝜈 𝐽 ,𝐾=𝜈0+ (𝐴′ −~𝐵′)+[ Δ 𝐴− Δ~𝐵 ] 𝐾2 ± 2 (𝐴′ −~𝐵′ )𝐾Q branch
a-type
b-type & c-type
Rotational constants of vibrational ground state
M. Nakagima and Y. Endo, J. Chem. Phys. 139, 101103 (2013)
Cs
-15 -10 -5 0 5 10 15
4.0
4.1
4.2
4.3
4.4
4.5
4.6
4.7
R
spac
ing
(K2)
P
V8
y = -0.023 x+ 4.33
0
2
900 890 880 870 860 850 840 830 820 810 800
0
2
A
bsor
banc
e / 1
0-
Wavenumber / cm-
Expt. 1 cm-1
8
Spectral analysis of ν8
CH2 wagging (ν8) c-type
0
2
900 890 880 870 860 850 840 830 820 810 800
0
2
RQ6RQ
5RQ
4RQ
3PQ
5PQ
6PQ
7PQ
8
A
bsor
banc
e / 1
0-
Wavenumber / cm-
Δ𝜈= [ Δ 𝐴− Δ 𝐵 ] Δ(𝐾¿¿2)+2 (𝐴′ −𝐵′ )¿
cm-1 ground ν8
ν 847.3
A 2.59355 2.57862
B 0.41580 0.41475
C 0.35762 0.35807
0
5
0
2
Simulation
RQ6RQ
5RQ
4RQ
3PQ
5PQ
6PQ
7PQ
8
Expt. 0.25 cm-1
Expt. -0.023 2.17
simulation -0.015 2.19
0
2
4
950 940 930 920 910 900 890 880 870 8600
2
4
A
bsor
banc
e / 1
0-
Wavenumber / cm-
Expt. 1 cm-1
9
Spectral analysis of ν6
O-O stretching (ν6) a-type:b-type = 0.98:0.02
Δ𝜈=¿
9
𝜈 𝐽 ,𝐾=𝜈0+ [ Δ 𝐴− Δ 𝐵 ] 𝐾2+∆𝐵𝐽 ( 𝐽+1 )
Δ B < 0
Δ A -Δ B <0, from Q
cm-1 ground ν6
ν 909.2
A 2.59355 2.57880
B 0.41580 0.41330
C 0.35762 0.35539
Expt. 0.25 cm-1
0
2
4
0
2
4
Simulation
RQ6RQ
5RQ
4RQ
3PQ
5PQ
6PQ
7PQ
8
Expt. 0.25 cm-1
Δ𝜈=2𝐵′+2 Δ 𝐵( 𝐽+1)
0
2
4
6
0
2
4
6
1480 1460 1440 1420 1400 1320 1300 1280 1260 1240
0
1
2
3
Expt. 0.25 cm-1
Simulation
Expt. 1 cm-1
Wavenumber / cm-
A
bsor
banc
e / 1
0-
10
Simulation of ν3 and ν4
CH2 scissor/ C=O str. (ν3)a-type:b-type = 0.99:0.01
cm-1 ground ν3 ν4
ν 1434.1 1285.7
A 2.59355 2.59976 2.5954
B 0.41580 0.41504 0.4190
C 0.35762 0.35658 0.3540 C=O str./CH2 scissor (ν4)a-type:b-type=0.88:0.12
0
1
2
0
1
2
1480 1460 1440 1420 1400 1320 1300 1280 1260 1240
0
1
2
3
Expt. 0.25 cm-1
Simulation
Expt. 1 cm-1
Wavenumber / cm-
A
bsor
banc
e / 1
0-
Expt. 1 cm-1
11
Simulation of ν5
0
1
2
1290 1280 1270 1260 1250 1240 1230 1220 1210 1200 1190 1180
0
1
2
A
bsor
banc
e / 1
0-
Wavenumber / cm-
CH2 rocking (ν5)a-type:b-type = 0.53:0.47
cm-1 ground ν5
ν 1241
A 2.59355 2.61000
B 0.41580 0.41641
C 0.35762 0.35627
?
Expt. 0.25 cm-1
0
1
2
0
1
2
Simulation
CH2I + O2 → CH2IOO*
CH2OO + I↓
0
1
0
1
0
1
1400 1300 1200 1100 1000 900 8000
1
102 torr
A
bsor
banc
e/ 1
0-2
206 torr
303 torr
wavenumber / cm-1
403 torr
12
Pt = 102 torr
Pt = 206 torr
Pt = 303 torr
CH2I2/N2/O2 + 308 nm under different PN2 1-7 μs, R = 1cm-1
Pt = 403 torr
0
5
0
20
40
substracted spectraPt= 403 torr
A
bsor
banc
e/ 1
0-3
simulation of CH2IOO
Inte
nsity
/ ar
b. u
nit
0
4
8
1340 1320 1300 1280 1260 1240 1220 1200 1180
0
4
8
Expt. 0.5 cm-1
Simulation
b
sorb
ance
/ 10
-
Wavenumber / cm-
Observed spectra of CH2IOO and simulations
CH2I2/O2/N2 (0.06/16/94)@308 nm, Pt = 300 torr
CH2OO ν4
CH2IOO ν4 = 1233.6 cm-1
CH2IOO ν5 = 1228 cm-1
13
0
1
2
1290 1280 1270 1260 1250 1240 1230 1220 1210 1200 1190 11800
1
A
bsor
banc
e / 1
0-
Wavenumber / cm-
Expt. 1 cm-1
14
Simulation of ν5
CH2 rocking (ν5)a-type:b-type = 0.53:0.47
?Expt. 0.25 cm-1
0
1
2
1290 1280 1270 1260 1250 1240 1230 1220 1210 1200 1190 11800
1
A
bsor
banc
e / 1
0-
Wavenumber / cm-
1213 cm-1
CH2IOO : ν4 = 1233.6 cm-1, ν5 =1228 cm-1
Simulation
ν5 of CH2OO ?
0
2
4
0
2
4
1350 1300 1250 1200 1150 950 900 850 8000
6
12
Expt.
Simulation
Wavenumber / cm-
SimulationA
bsor
banc
e / 1
0-
15
Identification of Dioxirane ?Comparison of observed spectrum with simulated spectrum (0.25 cm-1)
1290 1280 1270 1260 1250 1240 1230 1220 1210 1200 1190 1180
0.0
1.5
3.0
Wavenumber / cm-
b
sorb
ance
/ 10
- Expt.
simulation
16
cm-1 ground ν3 ν7
ν dioxirane 1231.5 1213.2
A 0.96657 0.9715 0.9605
B 0.83578 0.8372 0.8302
C 0.49301 0.4945 0.4966 C-O sym. str. (ν3)b-type
CH2 rock (ν7)c-typeSuenram and Lovas, J. Am. Chem. Soc. 100, 5117 (1978)
Dioxirane: ν3 and ν7
1290 1280 1270 1260 1250 1240 1230 1220 1210 1200 1190 1180
0.0
1.5
3.0
Wavenumber / cm-
b
sorb
ance
/ 10
- Expt.
simulation
1290 1280 1270 1260 1250 1240 1230 1220 1210 1200 1190 1180
0.0
1.5
3.0
Wavenumber / cm-
b
sorb
ance
/ 10
- Expt.
simulation
1290 1280 1270 1260 1250 1240 1230 1220 1210 1200 1190 1180
0.0
1.5
3.0
Wavenumber / cm-
b
sorb
ance
/ 10
- Expt.
simulationν5 of CH2OO : 1230.7 cm-1
17
cm-1 ground ν3 ν7
ν dioxirane 1231.5 1213.2
A 0.96657 0.9715 0.9605
B 0.83578 0.8372 0.8302
C 0.49301 0.4945 0.4966 C-O sym. str. (ν3)b-type
CH2 rock (ν7)c-type
Dioxirane: ν3 and ν7
Suenram and Lovas, J. Am. Chem. Soc. 100, 5117 (1978)
1290 1280 1270 1260 1250 1240 1230 1220 1210 1200 1190 1180
0.0
1.5
3.0
Wavenumber / cm-
b
sorb
ance
/ 10
- Expt.
simulation
18
cm-1 ground ν9
ν dioxirane 899.8
A 0.96657 0.95956
B 0.83578 0.83700
C 0.49301 0.50264C-O asym. str. (ν9)
a-type
Dioxirane: ν9
Suenram and Lovas, J. Am. Chem. Soc. 100, 5117 (1978)
950 940 930 920 910 900 890 880 870 860
0
5
Wavenumber / cm-
b
sorb
ance
/ 10
-
Expt. 0.25 cm-1
Simulation
950 940 930 920 910 900 890 880 870 860
0
5
Wavenumber / cm-
b
sorb
ance
/ 10
-
Expt. 0.25 cm-1
Simulation
0
3
1450 1400 1350 1300 1250 1200 950 900 850 8000
3
Expt. 0.25 cm-1
Sum of Simulation
Wavenumber / cm-
A
bsor
banc
e / 1
0-
1. High resolution IR spectrum of CH2OO• definative assignment of ν3, ν4, ν6 and ν8
• ν5 was misassigned• band origins of ν3, ν4, ν6 and ν8 are determined
19
Summary
CH2OO ν3 ν4 ν5 ν6 ν8
Expt. 1434.1 (15) 1285.7 (32
) 1230.7 (8) 909.2 (100) 847.3 (12
)
Theo. 1458 (31) 1302 (16
) 1220 (18) 892 (106
) 853 (30)
0
3
1450 1400 1350 1300 1250 1200 950 900 850 8000
3
Expt. 0.25 cm-1
Sum of Simulation
Wavenumber / cm-
A
bsor
banc
e / 1
0-
20
Summary2. IR absorption spectrum of CH2IOO
• overlapped bands of ν4 / ν5 and ν7 (overlapped with CH2OO)• yield increases with pressure
CH2IOO ν4 ν5 ν7
Expt. 1233.6 (27) 1228 (6) 919 (13)
p-H2 Matrix 1231.8 (53) 1225.6/1226.5 (19) 917.7 (50)
Theo. 1235 (28) 1231 (35) 901.4 (50)
0
3
1450 1400 1350 1300 1250 1200 950 900 850 8000
3
Expt. 0.25 cm-1
Sum of Simulation
Wavenumber / cm-
A
bsor
banc
e / 1
0-
21
Summary
3. Possible observation of Dioxirane
Dioxirane ν3 ν7 ν9
Expt. 1231.5 (23) 1213.2 (2) 899.8 (10)
Theo. 1238 (48) 1149 (7) 911 (26)
0
3
1450 1400 1350 1300 1250 1200 950 900 850 8000
3
Expt. 0.25 cm-1
Sum of Simulation
Wavenumber / cm-
A
bsor
banc
e / 1
0-
2. IR absorption spectrum of CH2IOOCH2IOO ν4 ν5 ν7
Expt. 1233.6 (27) 1228 (6) 919 (13)
p-H2 Matrix 1231.8 (53) 1225.6/1226.5 (19) 917.7 (50)
Theo. 1235 (28) 1231 (35) 901.4 (50)
22
Thanks for your attention!
Acknowledements:• Prof. Yuan-Pern Lee• Kuo-Hsiang Hsu, Yu-Te Su, and all the group members• National Science Council of Taiwan and the Ministry of Education
23
0
1
0
1
0
1
1400 1300 1200 1100 1000 900 8000
1
102 torr
206 torr
A
bsor
banc
e/ 1
0-2
wavenumber / cm-1
303 torr
403 torr
24
Pt = 102 torr
Pt = 206 torr
Pt = 303 torr
Pt = 403 torr
Subtracted spectra: spectra of CH2IOO
1-7 μs, R = 1cm-1
25
0
5
1400 1300 1200 1100 1000 900 800
0
20
40
exptl. spectra403 torr
A
bsor
banc
e/ 1
0-3
simulation cis-CH2IOO
Inte
nsity
/ ar
b. u
nit
Wavenumber / cm-1
Observed spectra of CH2IOO and simulations
ν0 and relative intensity adopted from spectra in p-H2 matrix
1340 1320 1300 1280 1260 1240 1220 1200 1180
0
4
8
Wavenumber / cm-
b
sorb
ance
/ 10
-
26
Observed spectra of CH2IOO and simulations
CH2I2/O2/N2 (0.06/16/94)@308 nm, Pt = 300 torr
27
ν7νC-O/wCH2
ν6νO-O/wCH2
ν3sCH2
ν4rCH2
ν5tCH2
ν8wCH2
Mode description p-H2 matrix
COO deform. 490.2C-I str. 550.5
CH2 wag. 841.6/841.1C-O 917.7O-O 1085.6
CH2 torsion 1225.6/1226.5CH2 rock 1231.8CH2 sci. 1408.9CH2 str. 2982.4
ν: stretch, δ: bend or deformation, δs: scissor, ω: wag, ρ: rock, τ: torsion
28
1450 1400 1350 1300 1250 1200 950 900 850 800
0
1
2
3
4
5
b
sorb
ance
/ 10
-
Wavenumber / cm-
Observed spectra of CH2OO and simulationsCH2OO υ(0.25 cm-1) Normalize
ν4 1285.7 32ν5 1230.7 8
dioxirane υ(0.25 cm-1) ν3 1231.5 23ν7 1213.2 2
CH2IOO υ(0.25 cm-1) ν4 1233.6 5ν5 1228 1
CH2OO υ(0.5 cm-1) Normalizeν4 1285.7 32ν5 1230.7 8
dioxirane υ(0.5 cm-1) ν3 1231.5 15ν7 1213.2 1
CH2IOO υ(0.5 cm-1) ν4 1233.6 27ν5 1228 6
29
0
10
0
3
6
1340 1320 1300 1280 1260 1240 1220 1200 1180 1160
0
1
308 nm40 torr
308 nm300 torr
248 nm95 torr
30
0
20
0
5
10
960 940 920 900 880 860
0
3
308 nm40 torr
308 nm300 torr
248 nm95 torr
0
2
4
950 940 930 920 910 900 890 880 870 8600
2
4
A
bsor
banc
e / 1
0-
Wavenumber / cm-
Expt. 1 cm-1
0
2
4
950 940 930 920 910 900 890 880 870 8600
2
4
A
bsor
banc
e / 1
0-
Wavenumber / cm-
31
Spectroscopic analysis of ν6
O-O stretching (ν6) a-type:b-type = 0.98:0.02
Δ𝜈=2𝐵′+2 Δ 𝐵( 𝐽+1) Δ𝜈=¿
31
𝜈 𝐽 ,𝐾=𝜈0+ [ Δ 𝐴− Δ 𝐵 ] 𝐾2+∆𝐵𝐽 ( 𝐽+1 )
Δ B < 0
Δ A -Δ B <0, from Q
cm-1 ground ν6
ν 909.2
A 2.59355 2.57880
B 0.41580 0.41330
C 0.35762 0.35539
Expt. 0.25 cm-1
0
2
4
0
2
4
Simulation
RQ6RQ
5RQ
4RQ
3PQ
5PQ
6PQ
7PQ
8
5 10 15 20 25 300.55
0.60
0.65
0.70
0.75
R branch
spac
ing
J+10 5 10 15 20 25
0.81
0.84
0.87
P branch
spac
ing
(2J+1)
