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Radical Intermediates in the Addition of OH to Propene: Photolytic Precursors and Angular Momentum Effects
ISMS 2014Matthew Brynteson, Carrie Womack, Ryan Booth,
Shih-Huang Lee, Jim Lin, and Laurie Butler
OH + Propene
+
OH propene
193 nm
193 nm
2-bromo-1-propanol
1-bromo-2-propanol
CCSD(T)/cc-PVDZ//B3LYP/cc-pVDZHuynh et al. J. Phys. Chem. A, 2009, 113, 3177-3185.
CCDCamera
MCP Detector & Phosphor
ScreenElectrostatic Lenses
Photolysis Laser (193 nm)
Pulsed Valve
skimmer
+2000 V +1424 V ground
REMPI for Br and Br*
10.5 eV Photoionization
750V
He
Velocity Map Imaging Apparatus
70% 1-bromo-2-propanol30% 2-bromo-1-propanol
𝐸𝑣𝑖𝑏=𝐸h𝑣+𝐸𝑝𝑟𝑒𝑐𝑢𝑟𝑠𝑜𝑟 −𝐸𝑇 −𝐷0 (𝐶−𝐵𝑟 )−𝐸𝑟𝑜𝑡−𝐸𝐵𝑟 ( 𝑃❑2
𝐽 )
0
0.02
0.04
0.06
0.08
0.1
0 10 20 30 40 50 60
P(E
T)
Energy, kcal/mol
-0.0002
0
0.0002
0.0004
0.0006
0.0008
0 1000 2000 3000 4000
P(v
)
Speed (m/s)0
10
20
30
40
50
60
70
80
0 20 40 60 80 100Time-of-Flight (sec)
m/z = 31 (CH2OH+)
Sig
na
l C
ou
nts
�⃑�❑=𝒓 × �⃑�𝒓�⃑� 𝐸𝑟𝑜𝑡=
12�⃑� 𝑇❑ 𝑰
−𝟏 �⃑�❑
C3H6OH Ethene + CH2OH+ionization
C3H6OH+dissociation
Dissociation!
0 0.2 0.4 0.6 0.8 1
P(E
T"/
ET')
ET"/E
T'
ET’ ET”
30 kcal/mol
Radical + Br
30 kcal/mol
30 kcal/mol
9 – 18 kcal/mol
OH + Propene
3 – 12 kcal/mol0 – 4.5 kcal/mol
𝑰−𝟏 �⃑�=�⃑�
𝑣=�⃑� × r⃑
Erot = 19 kcal/mol
0
0.1
0.2
0.3
0.4
0.5
0 5 10 15 20 25 30
P(E
T")
ET" (kcal/mol)
0
1 10-6
2 10-6
3 10-6
4 10-6
5 10-6
0 1000 2000 3000 4000 5000
P(v
)
v, speed (m/s)
0
2 10-6
4 10-6
6 10-6
8 10-6
1 10-5
0 500 1000 1500 2000 2500 3000
P(v
)
v, speed (m/s)
0
400
800
1200
1600
0 28 56 84 112 140
Sig
nal
Co
un
ts
m/z = 42 (C3H
6
+)
Time-of-Flight (sec)
0
100
200
300
400
500
600
7000 50 100 150 200 250
Time-of-Flight (sec)S
ign
al C
ou
nts
m/z = 17 (OH+)
OH Net Speed
Propene Net Speed
radicalOH
Net velocity
OH Net Speed
CD2CD2 Net Speed
radicalOH
Net velocity
-50
0
50
100
150
200
250
300
350
0 30 60 90 120
Sig
nal
Co
un
ts
Time-of-Flight (sec)
m/z = 32 (CD2CD
2
+)
0
100
200
300
400
500
600
7000 42.5 85 127.5 170
Sig
nal
Co
un
ts
Time-of-Flight (sec)
m/z = 17 (OH+)
0
1 10-6
2 10-6
3 10-6
4 10-6
5 10-6
0 1000 2000 3000 4000 5000
P(v
)
v, speed (m/s)
0
1 10-6
2 10-6
3 10-6
4 10-6
5 10-6
6 10-6
7 10-6
0 500 1000 1500 2000 2500 3000 3500
P(v
)
v, speed (m/s)
193 nm+
Thank You!• Butler Group– Dr. Carrie Womack*– Dr. Ryan Booth*– Dr. Chow-Shing Lam*– Lei Wang– Jon Adams– Preston Scrape– Prof. Laurie Butler*
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