S
1
A
-
Band
Absorption
Spectrum of
the
ClSO Radical
:
Electronic Structure of
the
Sulfinyl Group
Wen Chao,
‡,
*
Gregory H. Jones,
‡
Mitchio Okumura,
‡,
*
Carl J. Percival,
†
Frank A. F. Winiberg
†,
*
‡
Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd, Pasadena, CA
91128 United States
†
Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109
-
8099, United States
*Email:
fred.a.winiberg@jpl.nasa.gov
*Email:
mo
@
caltech.edu
*Email:
wchao
@
caltech.edu
Table of Contents
Absorption Spectrum of the Cl
2
SO Sample (Fig S1)
S2
Comparison of the Temporal Profiles (Fig S2)
S3
Concentration Dependence of the Weak Band (Fig S3
-
S4)
S4
Absorption Cross Section of ClSO (Fig S5)
S5
Vibrational Progression Analyses (
Fig S
6
)
S
5
Simulated Spectrum of displaced Harmonic Oscillator Models
(
Fig S
7
)
S
6
Bending Potential Energy Curves (Fig S
8
-
S1
0
)
S
7
Detailed Contributions of HEAT Methods
(
Table
S
1
)
S
8
Molecular Orbital Diagram of ClSO Radical
(
Fig S1
1
)
S
9
References
S1
0
S
2
Absorption Spectrum of the Cl
2
SO Sample
Figure S1.
Absorption
s
pectrum of the Cl
2
SO
s
ample
used in this study without further purifications
.
The distinct spectral lines, represented by various colors, correspond to different centers of wavelength.
The concentration of
Cl
2
SO
was
adjusted
to be 3.1
́
10
15
molecules
cm
-
3
,
the same
as
the experimental
conditions
shown
in Figure 1. The black circles indicate the absorption cross section from
Ref
1
.
250
300
350
400
450
500
550
600
10
-22
10
-21
10
-20
10
-19
10
-18
10
-17
Uthman et al.
Absoprtion Cross Section / cm
2
Wavelength / nm
This work
10
-4
10
-3
10
-2
10
-1
10
0
Absorbance
S
3
Comparison of the Temporal Profiles
Fig
ure
. S2.
Temporal
p
rofile
s
of the Cl
2
SO/N
2
/248 nm
s
ystem
,
monitored near 303 nm (black,
1
2
A"
←
X
2
A"
) and 370 nm (blue,
2
2
A'
←
X
2
A"
) under a pressure of 40 Torr. The observed temporal profiles are
roughly
consistent with each other, although the decay rate at 303 nm is slightly slower. Given the high
concentration of Cl
2
SO ([Cl
2
SO] = 7.5
́
10
14
cm
-
3
), the
products from the
secondary chemistry, which
could
generate species with the SO group and exhibit strong absorption near 300 nm,
might be observed
.
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Normalized Intensity / arb.
Time / ms
370 nm
303 nm
S
4
Concentration Dependence of the Weak
Band
Fig
ure
. S
3
.
Recorded
s
pectrum of the
w
eak
a
bsorption
b
and (Center Wavelength = 370 nm) under
distinct
[Cl
2
SO]
for 2048 shots average
.
Fig
ure
. S
4
.
Plot of
o
bserved
D
A
bs
.
(380
-
390 nm
average
) versus [Cl
2
SO]
, including the data from
Figure 1 and Figure S3. At the highest [Cl
2
SO] concentrations, the observed absorp
tion deviates from
the linear
region,
showing the effect of
absorption from the C
l2
SO sample affecting the photolysis laser.
320
340
360
380
400
420
0
2
4
6
8
10
D
Absorbance
/ 10
-
3
Wavelength / nm
[Cl
2
SO] / 10
14
cm
-
3
3.7
6.7
7.5
13.3
0
5
10
15
20
25
30
35
0
1
2
3
4
5
6
7
8
9
10
D
Abs.
(380
-
390 nm) / 10
-
3
[Cl
2
SO] / 10
14
cm
-
3
S
5
Absorption Cross Section of ClSO
Fig
ure
. S5.
(Left)
Comparison of absorption cross sections for the 1
2
A"
←
X
2
A" transition (black, Ref
2
)
and the 2
2
A'
←
X
2
A" transition (blue) of ClSO radical.
(Right) The calculated absolute cross section of
both the
1
2
A"
←
X
2
A" and the 2
2
A'
←
X
2
A"
transitions.
Vibrational Progression Analyses
Figure. S6.
A
closer
look
of the small structures in the valley region within the 312.5
-
385 nm. The
origin of the
1
2
A"
←
X
2
A"
transition is also indicated.
260
280
300
320
340
360
380
400
420
440
460
480
10
-21
10
-20
10
-19
10
-18
Absolute Cross Section / cm
-
2
Wavelength / nm
260
280
300
320
340
360
380
400
420
440
460
480
10
-21
10
-20
10
-19
10
-18
Absolute Cross Section / cm
-
2
Wavelength / nm
Sum
1
2
A'
¬
X
2
A"
2
2
A'
¬
X
2
A"
32000
31000
30000
29000
28000
27000
26000
312.5
322.6
333.3
344.8
357.1
370.4
384.6
0
2
4
6
8
10
D
Large
= 1052.0 cm
-
1
D
Large
= 1068.4 cm
-
1
D
Small
= 358.4 cm
-
1
Wavelength / nm
D
Absorbance
/ 10
-
3
Wavenumber / cm
-
1
Origin of 1
2
A"
¬
X
2
A"
D
Small
= 374.8 cm
-
1
S
6
Simulated Spectrum of Displaced Harmonic Oscillator Models
Figure. S
7
.
The r
ecorded spectrum of the Cl
2
SO/N
2
/248 nm
system at
100
μ
s after pulsed laser
(
exposure
time =
117.5
μ
s
,
averaged
for
12288 shots)
under 40 Torr
. Cyan
, blue, and red lines represent
spectra at different grating angles (center wavelengths of 370 nm, 420 nm, and 520 nm), while the gray
lines show the background noise without Cl
2
SO.
The downward
stick spectra are the transitions to
the
1
2
A
'
(orange, ×10
6
) and 2
2
A' (
olive
) state
s
predicted by
the EOMEE
-
CCSD
/ano
-
PVQZ
calculations
.
Note that the Frank
-
Condon factors of the 1
2
A
'
state
is six orders of magnitude smaller than the 2
2
A
'
state
. The black line is the simulated spectrum to both states (stick spectra convoluted with a Gaussian
function
with FWHM = 150 cm
-
1
).
320
340
360
380
400
420
440
460
480
500
520
540
560
580
-8
-6
-4
-2
0
2
4
6
8
10
D
Absorbance
/ 10
-
3
Wavelength / nm
́
10
6
S
7
Bending
Potential Energy Curves
Figure. S
8
.
Changes in ClS,
r
Cl
S
, and SO,
r
SO
,
b
ond
l
ength
in the scan of the bending potential energy
curves,
as repr
esented in
Figure S
8
-
S
9
. The coord
inates were generated by linearly connecting the
energy minimum geometries of the 2
2
A', X
2
A" and 1
2
A' excited states
in the order from small angle to
large angle.
Fig
ure
. S
9
.
Bending
p
otential
e
nergy
c
urves
calculated at the EOMEA
-
CCSD/ano
-
p
VTZ level for the
1
2
A' excited state (
orange) and at the EOMIP
-
CCSD/
ano
-
pVTZ
level for the 2
2
A' excited state
(
olive).
Associated geometric parameters are given in Figure S7.
A cross between these two curves
near
the
minimum X
2
A" geometry
suggests
the existence of a conical intersection.
80
100
120
140
160
180
1.4
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5
r
ClS
r
SO
Bond Length /
Å
Ð
ClSO / degree
80
90
100
110
120
130
140
150
160
170
180
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
X
2
A"
1
2
A'
Energy / eV
Ð
ClSO / degree
EOMIP
EOMEA
CCSD/ano-PVTZ
2
2
A'
S
8
Figure. S
10
.
Bending
p
otential
e
nergy
c
urves calculated at the EOMEE
-
CCSD/ano
-
p
VTZ level for the
1
2
A' and 2
2
A' excited states.
Associated geometric parameters are given in Figure S7.
At the minimum
X
2
A" geometry, the excitation energy for the second A' state failed to converge
.
D
etailed Contributions
of HEAT Method
Table S1.
Indivi
d
ual contributions to the
HEAT total energies
(
in
H
a
rtree
) and the standard enthalpy
change at 0 K.
Species
E
∞
HF
Δ
E
∞
CCSD(T)
Δ
E
CCSDT
Δ
E
CCSDTQ
Δ
E
REL
Δ
E
DBOC
Δ
E
SO
a
Δ
E
ZPE
Total
Cl
-
459.489895
-
0.665245
-
0.000767
-
0.000161
-
1.404007
0.005940
-
0.0013
38
0.000000
-
461.55547
3
ClSO
-
931.946359
-
1.683349
-
0.000890
-
0.001801
-
2.533727
0.013978
0.000000
0.004539
-
936.147609
SO
-
472.421430
-
0.962796
-
0.000481
-
0.001299
-
1.129986
0.008022
0.000000
0.002626
-
474.505345
Reaction
Δ
H
°
(0 K, HEAT) / kJ mol
-
1
Cl
S
O
→
Cl + SO
227.869
a
Values
adopted from the CCCBDB database, II.C.2 Electronic Spin Splitting Corrections.
80
90
100
110
120
130
140
150
160
170
180
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
X
2
A"
1
2
A'
Energy / eV
Ð
ClSO / degree
EOMEE-CCSD/ano-pVTZ
2
2
A'
S
9
Mol
ecular Orbital Diagram of ClSO R
adical
Figure. S1
1
.
The
molecular orbital diagram
of ClSO
radical, considering the valence orbitals of SO
molecules and the 3
p
orbital of Cl atoms. T
he green lines indicate
the interaction of out
-
of
-
plane
(A”)
orbitals.
Overall,
the
total 9 molecular orbitals
are
classified as bonding,
total
non
-
bonding and
anti
-
bonding.
SO
Cl
Bonding
(
s
/
p
)
Total Non
-
Bonding
Anti
-
Bonding
(
s
*/
p
*
)
2
p
*
2
p
6
s
7
s
3
p
S
10
References
(1)
Uthman, A. P.; Demlein, P. J.; Allston, T. D.; Withiam, M. C.; McClements, M. J.; Takacs, G. A.
Photoabsorption Spectra of Gaseous Methyl Bromide, Ethylene Dibromide, Nitrosyl Bromide,
Thionyl Chloride, and Sulfuryl Chloride.
J. Phys. Chem.
1978
,
82
(20), 2252
–
2257.
https://doi.org/10.1021/j100509a021.
(2)
Chao, W.; Jones, G. H.; Okumura, M.; Percival, C. J.; Winiberg, F. A. F. Spectroscopic and Kinetic
Studies of the ClSO Radical from Cl
2
SO Photolysis.
J. Am. Chem. Soc.
2022
,
144
(44), 20323
–
20331. https://doi.org/10.1021/jacs.2c07912.