S1
Chemical Kinetic Study of the Reaction of CH
2
OO with CH
3
O
2
Wen Chao,
‡,*
Charles R. Markus,
†
Mitchio Okumura,
‡
Frank A. F. Winiberg
†
, Carl J. Percival,
†,*
‡
Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd, Pasadena, CA
91125 United States
†
NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099, United
States
*Email:
wchao@caltech.edu
*Email: carl.j.percival@jpl.nasa.gov
Table of Contents
Summary of the Absorption Cross Sections (Fig S1)
S2
Integrated signal intensities recorded at 45-55 ms after photolysis (Fig S2)
S3
Representative Spectra at 90 Torr and 238 K (Fig S3)
S4
The Spectra from CH
2
I
2
/O
2
/N
2
Photolysis at 238 K (Fig S4
S6)
S5
Spectroscopic and Kinetic Behavior of CH
3
OOI (Fig S7
S11)
S8
Decay Profiles of CH
2
OO in the absence of CH
3
O
2
(Fig S12
S14)
S13
Corrections to CH
2
OO traces due to the absorption of CH
3
OOI at 10 Torr and 294 K (Fig S15)
S18
Estimating the CH
3
and CH
3
O
2
Concentrations at 10 Torr and 294 K (Fig S16
S17)
S19
Summary of the Model Fit Results (Fig S18
S25 and Table S1)
S21
Test the Influences of CH
2
OO + HO
2
Reaction (Fig S26)
S30
References
S31
S2
Summary of the Absorption Cross Sections
2
6
0
2
8
0
3
0
0
3
2
0
3
4
0
3
6
0
3
8
0
4
0
0
4
2
0
4
4
0
4
6
0
4
8
0
-
4
-
2
0
2
4
6
8
1
0
1
2
1
4
C
H
3
I
C
H
2
I
2
C
H
3
O
2
C
H
2
O
O
0
.
5
I
O
A
b
s
o
r
p
t
i
o
n
C
r
o
s
s
S
e
c
t
i
o
n
/
1
0
1
8
c
m
2
W
a
v
e
l
e
n
g
t
h
/
n
m
I
2
Figure S1.
Summary of the absorption cross-sections for CH
2
OO,
1
CH
3
O
2
,
2
IO,
3
I
2
, CH
3
I,
4
and CH
2
I
2
.
4
The cross section of CH
2
OO below 260 nm is modeled as a Gaussian peak. The CH
3
I and CH
2
I
2
are
plotted negatively since the depletions of these two precursors result in a negative absorption in our
measurements. The cross section of I
2
was measured in this work and normalized between 420
490
nm.
5
S3
Integrated signal intensities recorded at 45-55 ms after photolysis
0
2
4
6
8
1
0
1
2
1
4
-
0
.
3
-
0
.
2
-
0
.
1
0
.
0
0
.
1
0
.
2
A
b
s
o
r
b
a
n
c
e
(
3
4
0
n
m
)
/
1
0
3
[
C
H
3
I
]
/
1
0
1
4
c
m
3
D
e
l
a
y
T
i
m
e
=
4
5
5
5
m
s
Figure S2.
The absorption signal at longer delay times (averaged between 45–55 ms) as a function of
CH
3
I concentration for figure 2A in the main text. The red line presents the linear fit to the data points.
Data were recorded in N
2
/CH
2
I
2
/CH
3
I/O
2
mixtures at 340 nm, 50 Torr total pressure.
S4
Representative Spectra recorded at 90 Torr and 238 K
0
4
8
1
2
A
b
s
o
r
b
a
n
c
e
/
1
0
3
[
C
H
2
I
2
]
=
6
.
6
1
0
1
3
c
m
3
[
C
H
3
I
]
=
0
c
m
3
D
e
l
a
y
T
i
m
e
/
m
s
0
.
1
1
3
1
5
0
4
8
1
2
A
b
s
o
r
b
a
n
c
e
/
1
0
3
D
e
l
a
y
T
i
m
e
/
m
s
0
.
1
1
3
1
5
[
C
H
3
I
]
=
1
.
1
1
0
1
5
c
m
3
[
C
H
2
I
2
]
=
6
.
5
1
0
1
3
c
m
3
2
7
5
3
0
0
3
2
5
3
5
0
3
7
5
4
0
0
4
2
5
4
5
0
4
7
5
0
4
8
1
2
A
b
s
o
r
b
a
n
c
e
/
1
0
3
W
a
v
e
l
e
n
g
t
h
/
n
m
[
C
H
2
I
2
]
=
0
c
m
3
[
C
H
3
I
]
=
1
.
1
1
0
1
5
c
m
3
D
e
l
a
y
T
i
m
e
/
m
s
0
.
1
1
3
1
5
Figure S3.
Representative absorption spectra from photolysis of mixtures containing (A) only CH
2
I
2
,
(B) both CH
2
I
2
and CH
3
I, and (C) only CH
3
I at selected delay times with gate width = 48
s and
averaged over 2048 photolysis laser shots. The spectra were recorded using a 300 grooves/mm grating at
center wavelength 340 nm. Note clear changes below 300 nm were observed. The experimental
conditions are
P
O2
= 4.9 Torr balanced with N
2
to 89.9 Torr at 238 K.
S5
The Spectra from CH
2
I
2
/O
2
/N
2
Photolysis at 238 K
-
2
0
2
4
6
2
0
T
o
r
r
,
D
e
l
a
y
=
0
.
1
m
s
A
b
s
o
r
b
a
n
c
e
/
1
0
3
E
x
p
.
C
H
2
I
2
C
H
2
O
O
I
O
I
2
F
i
t
.
2
0
T
o
r
r
,
D
e
l
a
y
=
1
m
s
E
x
p
.
C
H
2
I
2
C
H
2
O
O
I
O
I
2
F
i
t
.
2
8
0
3
0
0
3
2
0
3
4
0
3
6
0
3
8
0
4
0
0
4
2
0
4
4
0
4
6
0
-
2
0
2
4
6
2
0
T
o
r
r
,
D
e
l
a
y
=
3
m
s
A
b
s
o
r
b
a
n
c
e
/
1
0
3
W
a
v
e
l
e
n
g
t
h
/
n
m
E
x
p
.
C
H
2
I
2
C
H
2
O
O
I
O
I
2
F
i
t
.
2
8
0
3
0
0
3
2
0
3
4
0
3
6
0
3
8
0
4
0
0
4
2
0
4
4
0
4
6
0
2
0
T
o
r
r
,
D
e
l
a
y
=
1
5
m
s
W
a
v
e
l
e
n
g
t
h
/
n
m
E
x
p
.
C
H
2
I
2
C
H
2
O
O
I
O
I
2
F
i
t
.
Figure S4.
The recorded spectra from the photolysis of CH
2
I
2
/O
2
/N
2
/248 nm mixtures at selected delay
times with gate width = 48
s and averaged over 2048 photolysis laser shots. Each measured spectrum
can be attributed into the components of
CH
2
I
2
(red), CH
2
OO (cyan), IO (green) and I
2
, (violet),
indicating a lack of ICH
2
OO radicals. The experimental conditions are
P
O2
= 4.9 Torr, [CH
2
I
2
] =
7.8
10
13
cm
3
balanced with N
2
to 20 Torr at 238 K.