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ROTATIONALLY RESOLVED ELECTRONIC SPECTRA
OF SECONDARY ALKOXY RADICALS
062210
JINJUN LIU AND TERRY A MILLER
Laser Spectroscopy FacilityDepartment of Chemistry
The Ohio State University
PREDICTION AND DETERMINATION
OF SPIN-ROTATION CONSTANTS
OF NEARLY DEGENERATE ELECTRONIC STATES
aQ
Vethoxy
2 AA
2 AXhelliphellip
methoxyCH3OCD3O
CH2DO
CHD2O
ethoxy
iso-propoxy
1-propoxy
2-butoxy
cyclohexoxy
helliphellip
helliphellip
Alkoxy radicals (RO)
V
aQ2X E aQ
U
2X E aQ
U
2X E
ExcimerLaser(XeCl)
Pulse Dye Amplifier
Ar+ Laser CW RingDye Laser
Computer
XeFPhotolysis
Laser
PMT
DoublingCrystal
Hi-resolution LIF apparatus
Box-Car
EtalonPD
PDI2
Lock-in
X
B
RONO+He
LIF = laser-induced fluorescenceT~1Kspectral linewidth ~ 200 MHzfrequency accuracy ~ 50 MHz
(1) (2) (2)
1
(2)
ˆ ˆ
i j i j
R S
i L j i I L j c c
E E
ε Iε
ε ε
y
z
x
y
z
xb
a
c
b
a
c
UR
US
1 1 1S S S R R R R S
ε I U U I ε U U
Hamiltonian and prediction of spin-rotation tensor
ethoxy (R)
T 1-propoxy (S)
bull ldquoThe isotopic dependence of the spin-rotation interaction for an asymmetric top moleculerdquo J M Brown T J Sears and J K G Watson Mol Phys 41 173 (1980)
bull Theoretical Prediction of Spectroscopic Constants of 1-alkoxy Radicals G Tarczay S Gopalakrishnan and T A Miller J Mol Spectros 220 276 (2003)
bull ``Rotationally Resolved - Electronic Spectra of Both Conformers of the 1-Propoxy Radical S Gopalakrishnan C C Carter L Zu V Stakhursky G Tarczay and T A Miller J Chem Phys 118 4954 (2003)
Spin-rotation constants of 1-propoxy in GHz
Rot rotationalSR spin-rotation
T trans-G gauche-
ldquogeometry-fixed coordinate systemrdquoprincipal axis systemground (X) state excited (B) state
H = HRot + HSR H = HRot
HRot = ANa2 + BNb
2 + CNc2
HSR = frac12 αβ (NαSβ + SβNα)
R reference S substituted
a b
-25 -20 -15 -10 -5 0 5 10 15 20 25
0
100
200
300
400
500
600
700
rela
tive
en
erg
y (c
m-1)
tilt angle of O atom from Cs plane (degree)
-10 -5 0 5 10
0
100
200
300
400
500
600
700
rela
tive
en
erg
y (c
m-1)
tilt angle of O atom from Cs plane (degree)
2 A X
2 A A
in cm-1 ethoxyiso-
propoxy
Calcwo ZPE
wo ΔEPJT (Cs-Cs) +335 -122
w ΔEPJT (C1-Cs) +340 -24
w ZPE +508 -46
Exptdagger +355(10)
-68(10)
(A) (A)E E E
Iso-propoxy vs ethoxy
PJT pseudo-Jahn-Teller
2 A A
2A X
ΔEPJT=98 cm-1
dagger Dispersed Fluorescence Spectroscopy of Primary and Secondary Alkoxy Radicals J Jin I Sioutis G Tarczay S Gopalakrishnan A Bezant T A Miller J Chem Phys 121 11780 (2004)
iso-propoxy ethoxy
ldquogeometry-fixed coordinate systemrdquoldquoorbital-fixed coordinate systemrdquo
Common coordinates for prediction of SR tensor
a Geometry optimized at the B3LYP6-31G level of theory and used to calculate Us
b At the CIS6-31G level of theoryc In the ldquogeometry-fixed coordinate systemrdquo Scaled by A-X separationd In the ldquoorbital-fixed coordinate systemrdquo Scaled by A-X separation
Molecular constants of iso-propoxy in cm-1
27161 27162 27163 27164 27165 27166 27167 27168
frequency (cm-1)
simulation
expt
R(1)
R(4)
R(0)
R(2)
R(3)
Q-branch
P(4)
P(1)P(2)
P(3)
271654 271656 271658 271660 271662
frequency (cm-1)
simulation
expt
Iso-propoxy
(2)
ˆ ˆ 2
a a
aa
X A
X L A X AL A c c
E E
y(a)
z
x
b
c
transition typesabc=001
271618 271620 271622 271624 271626 271628
frequency (cm-1)
simulation
expt
ˆA A A AaLX A
270845 270850 270855 270860 270865 270870 270875 270880 270885 frequency (cm-1)
simulation
expt
a Geometry optimized at the UHF6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of T 2-butoxy in GHz
T conformer of 2-butoxy
transition typesabc=203
A XE =68(10) cm-1 55(10) cm-1
270540 270545 270550 270555 270560 270565 270570
frequency (cm-1)
simulation
expt
267525 267530 267535 267540 267545 267550 267555 267560
frequency (cm-1)
simulation
expt
Cyclohexoxy
a Geometry optimized at the B3LYP6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of cyclohexoxy in GHz
abc=100abc=010
BX transition to arsquo vibronic level (origin band)
BX transition to ardquo vibronic level BA transition to arsquo vibronic level
273790 273795 273800 273805 273810 273815 273820 frequency (cm-1)
simulation
expt
Summary and Future work
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Dr Phillip S Thomas
NSF$$$
NSF$$$
Thank you allThank
you all
Miller GroupMiller Group
Acknowledgements
aQ
Vethoxy
2 AA
2 AXhelliphellip
methoxyCH3OCD3O
CH2DO
CHD2O
ethoxy
iso-propoxy
1-propoxy
2-butoxy
cyclohexoxy
helliphellip
helliphellip
Alkoxy radicals (RO)
V
aQ2X E aQ
U
2X E aQ
U
2X E
ExcimerLaser(XeCl)
Pulse Dye Amplifier
Ar+ Laser CW RingDye Laser
Computer
XeFPhotolysis
Laser
PMT
DoublingCrystal
Hi-resolution LIF apparatus
Box-Car
EtalonPD
PDI2
Lock-in
X
B
RONO+He
LIF = laser-induced fluorescenceT~1Kspectral linewidth ~ 200 MHzfrequency accuracy ~ 50 MHz
(1) (2) (2)
1
(2)
ˆ ˆ
i j i j
R S
i L j i I L j c c
E E
ε Iε
ε ε
y
z
x
y
z
xb
a
c
b
a
c
UR
US
1 1 1S S S R R R R S
ε I U U I ε U U
Hamiltonian and prediction of spin-rotation tensor
ethoxy (R)
T 1-propoxy (S)
bull ldquoThe isotopic dependence of the spin-rotation interaction for an asymmetric top moleculerdquo J M Brown T J Sears and J K G Watson Mol Phys 41 173 (1980)
bull Theoretical Prediction of Spectroscopic Constants of 1-alkoxy Radicals G Tarczay S Gopalakrishnan and T A Miller J Mol Spectros 220 276 (2003)
bull ``Rotationally Resolved - Electronic Spectra of Both Conformers of the 1-Propoxy Radical S Gopalakrishnan C C Carter L Zu V Stakhursky G Tarczay and T A Miller J Chem Phys 118 4954 (2003)
Spin-rotation constants of 1-propoxy in GHz
Rot rotationalSR spin-rotation
T trans-G gauche-
ldquogeometry-fixed coordinate systemrdquoprincipal axis systemground (X) state excited (B) state
H = HRot + HSR H = HRot
HRot = ANa2 + BNb
2 + CNc2
HSR = frac12 αβ (NαSβ + SβNα)
R reference S substituted
a b
-25 -20 -15 -10 -5 0 5 10 15 20 25
0
100
200
300
400
500
600
700
rela
tive
en
erg
y (c
m-1)
tilt angle of O atom from Cs plane (degree)
-10 -5 0 5 10
0
100
200
300
400
500
600
700
rela
tive
en
erg
y (c
m-1)
tilt angle of O atom from Cs plane (degree)
2 A X
2 A A
in cm-1 ethoxyiso-
propoxy
Calcwo ZPE
wo ΔEPJT (Cs-Cs) +335 -122
w ΔEPJT (C1-Cs) +340 -24
w ZPE +508 -46
Exptdagger +355(10)
-68(10)
(A) (A)E E E
Iso-propoxy vs ethoxy
PJT pseudo-Jahn-Teller
2 A A
2A X
ΔEPJT=98 cm-1
dagger Dispersed Fluorescence Spectroscopy of Primary and Secondary Alkoxy Radicals J Jin I Sioutis G Tarczay S Gopalakrishnan A Bezant T A Miller J Chem Phys 121 11780 (2004)
iso-propoxy ethoxy
ldquogeometry-fixed coordinate systemrdquoldquoorbital-fixed coordinate systemrdquo
Common coordinates for prediction of SR tensor
a Geometry optimized at the B3LYP6-31G level of theory and used to calculate Us
b At the CIS6-31G level of theoryc In the ldquogeometry-fixed coordinate systemrdquo Scaled by A-X separationd In the ldquoorbital-fixed coordinate systemrdquo Scaled by A-X separation
Molecular constants of iso-propoxy in cm-1
27161 27162 27163 27164 27165 27166 27167 27168
frequency (cm-1)
simulation
expt
R(1)
R(4)
R(0)
R(2)
R(3)
Q-branch
P(4)
P(1)P(2)
P(3)
271654 271656 271658 271660 271662
frequency (cm-1)
simulation
expt
Iso-propoxy
(2)
ˆ ˆ 2
a a
aa
X A
X L A X AL A c c
E E
y(a)
z
x
b
c
transition typesabc=001
271618 271620 271622 271624 271626 271628
frequency (cm-1)
simulation
expt
ˆA A A AaLX A
270845 270850 270855 270860 270865 270870 270875 270880 270885 frequency (cm-1)
simulation
expt
a Geometry optimized at the UHF6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of T 2-butoxy in GHz
T conformer of 2-butoxy
transition typesabc=203
A XE =68(10) cm-1 55(10) cm-1
270540 270545 270550 270555 270560 270565 270570
frequency (cm-1)
simulation
expt
267525 267530 267535 267540 267545 267550 267555 267560
frequency (cm-1)
simulation
expt
Cyclohexoxy
a Geometry optimized at the B3LYP6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of cyclohexoxy in GHz
abc=100abc=010
BX transition to arsquo vibronic level (origin band)
BX transition to ardquo vibronic level BA transition to arsquo vibronic level
273790 273795 273800 273805 273810 273815 273820 frequency (cm-1)
simulation
expt
Summary and Future work
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Dr Phillip S Thomas
NSF$$$
NSF$$$
Thank you allThank
you all
Miller GroupMiller Group
Acknowledgements
ExcimerLaser(XeCl)
Pulse Dye Amplifier
Ar+ Laser CW RingDye Laser
Computer
XeFPhotolysis
Laser
PMT
DoublingCrystal
Hi-resolution LIF apparatus
Box-Car
EtalonPD
PDI2
Lock-in
X
B
RONO+He
LIF = laser-induced fluorescenceT~1Kspectral linewidth ~ 200 MHzfrequency accuracy ~ 50 MHz
(1) (2) (2)
1
(2)
ˆ ˆ
i j i j
R S
i L j i I L j c c
E E
ε Iε
ε ε
y
z
x
y
z
xb
a
c
b
a
c
UR
US
1 1 1S S S R R R R S
ε I U U I ε U U
Hamiltonian and prediction of spin-rotation tensor
ethoxy (R)
T 1-propoxy (S)
bull ldquoThe isotopic dependence of the spin-rotation interaction for an asymmetric top moleculerdquo J M Brown T J Sears and J K G Watson Mol Phys 41 173 (1980)
bull Theoretical Prediction of Spectroscopic Constants of 1-alkoxy Radicals G Tarczay S Gopalakrishnan and T A Miller J Mol Spectros 220 276 (2003)
bull ``Rotationally Resolved - Electronic Spectra of Both Conformers of the 1-Propoxy Radical S Gopalakrishnan C C Carter L Zu V Stakhursky G Tarczay and T A Miller J Chem Phys 118 4954 (2003)
Spin-rotation constants of 1-propoxy in GHz
Rot rotationalSR spin-rotation
T trans-G gauche-
ldquogeometry-fixed coordinate systemrdquoprincipal axis systemground (X) state excited (B) state
H = HRot + HSR H = HRot
HRot = ANa2 + BNb
2 + CNc2
HSR = frac12 αβ (NαSβ + SβNα)
R reference S substituted
a b
-25 -20 -15 -10 -5 0 5 10 15 20 25
0
100
200
300
400
500
600
700
rela
tive
en
erg
y (c
m-1)
tilt angle of O atom from Cs plane (degree)
-10 -5 0 5 10
0
100
200
300
400
500
600
700
rela
tive
en
erg
y (c
m-1)
tilt angle of O atom from Cs plane (degree)
2 A X
2 A A
in cm-1 ethoxyiso-
propoxy
Calcwo ZPE
wo ΔEPJT (Cs-Cs) +335 -122
w ΔEPJT (C1-Cs) +340 -24
w ZPE +508 -46
Exptdagger +355(10)
-68(10)
(A) (A)E E E
Iso-propoxy vs ethoxy
PJT pseudo-Jahn-Teller
2 A A
2A X
ΔEPJT=98 cm-1
dagger Dispersed Fluorescence Spectroscopy of Primary and Secondary Alkoxy Radicals J Jin I Sioutis G Tarczay S Gopalakrishnan A Bezant T A Miller J Chem Phys 121 11780 (2004)
iso-propoxy ethoxy
ldquogeometry-fixed coordinate systemrdquoldquoorbital-fixed coordinate systemrdquo
Common coordinates for prediction of SR tensor
a Geometry optimized at the B3LYP6-31G level of theory and used to calculate Us
b At the CIS6-31G level of theoryc In the ldquogeometry-fixed coordinate systemrdquo Scaled by A-X separationd In the ldquoorbital-fixed coordinate systemrdquo Scaled by A-X separation
Molecular constants of iso-propoxy in cm-1
27161 27162 27163 27164 27165 27166 27167 27168
frequency (cm-1)
simulation
expt
R(1)
R(4)
R(0)
R(2)
R(3)
Q-branch
P(4)
P(1)P(2)
P(3)
271654 271656 271658 271660 271662
frequency (cm-1)
simulation
expt
Iso-propoxy
(2)
ˆ ˆ 2
a a
aa
X A
X L A X AL A c c
E E
y(a)
z
x
b
c
transition typesabc=001
271618 271620 271622 271624 271626 271628
frequency (cm-1)
simulation
expt
ˆA A A AaLX A
270845 270850 270855 270860 270865 270870 270875 270880 270885 frequency (cm-1)
simulation
expt
a Geometry optimized at the UHF6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of T 2-butoxy in GHz
T conformer of 2-butoxy
transition typesabc=203
A XE =68(10) cm-1 55(10) cm-1
270540 270545 270550 270555 270560 270565 270570
frequency (cm-1)
simulation
expt
267525 267530 267535 267540 267545 267550 267555 267560
frequency (cm-1)
simulation
expt
Cyclohexoxy
a Geometry optimized at the B3LYP6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of cyclohexoxy in GHz
abc=100abc=010
BX transition to arsquo vibronic level (origin band)
BX transition to ardquo vibronic level BA transition to arsquo vibronic level
273790 273795 273800 273805 273810 273815 273820 frequency (cm-1)
simulation
expt
Summary and Future work
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Dr Phillip S Thomas
NSF$$$
NSF$$$
Thank you allThank
you all
Miller GroupMiller Group
Acknowledgements
(1) (2) (2)
1
(2)
ˆ ˆ
i j i j
R S
i L j i I L j c c
E E
ε Iε
ε ε
y
z
x
y
z
xb
a
c
b
a
c
UR
US
1 1 1S S S R R R R S
ε I U U I ε U U
Hamiltonian and prediction of spin-rotation tensor
ethoxy (R)
T 1-propoxy (S)
bull ldquoThe isotopic dependence of the spin-rotation interaction for an asymmetric top moleculerdquo J M Brown T J Sears and J K G Watson Mol Phys 41 173 (1980)
bull Theoretical Prediction of Spectroscopic Constants of 1-alkoxy Radicals G Tarczay S Gopalakrishnan and T A Miller J Mol Spectros 220 276 (2003)
bull ``Rotationally Resolved - Electronic Spectra of Both Conformers of the 1-Propoxy Radical S Gopalakrishnan C C Carter L Zu V Stakhursky G Tarczay and T A Miller J Chem Phys 118 4954 (2003)
Spin-rotation constants of 1-propoxy in GHz
Rot rotationalSR spin-rotation
T trans-G gauche-
ldquogeometry-fixed coordinate systemrdquoprincipal axis systemground (X) state excited (B) state
H = HRot + HSR H = HRot
HRot = ANa2 + BNb
2 + CNc2
HSR = frac12 αβ (NαSβ + SβNα)
R reference S substituted
a b
-25 -20 -15 -10 -5 0 5 10 15 20 25
0
100
200
300
400
500
600
700
rela
tive
en
erg
y (c
m-1)
tilt angle of O atom from Cs plane (degree)
-10 -5 0 5 10
0
100
200
300
400
500
600
700
rela
tive
en
erg
y (c
m-1)
tilt angle of O atom from Cs plane (degree)
2 A X
2 A A
in cm-1 ethoxyiso-
propoxy
Calcwo ZPE
wo ΔEPJT (Cs-Cs) +335 -122
w ΔEPJT (C1-Cs) +340 -24
w ZPE +508 -46
Exptdagger +355(10)
-68(10)
(A) (A)E E E
Iso-propoxy vs ethoxy
PJT pseudo-Jahn-Teller
2 A A
2A X
ΔEPJT=98 cm-1
dagger Dispersed Fluorescence Spectroscopy of Primary and Secondary Alkoxy Radicals J Jin I Sioutis G Tarczay S Gopalakrishnan A Bezant T A Miller J Chem Phys 121 11780 (2004)
iso-propoxy ethoxy
ldquogeometry-fixed coordinate systemrdquoldquoorbital-fixed coordinate systemrdquo
Common coordinates for prediction of SR tensor
a Geometry optimized at the B3LYP6-31G level of theory and used to calculate Us
b At the CIS6-31G level of theoryc In the ldquogeometry-fixed coordinate systemrdquo Scaled by A-X separationd In the ldquoorbital-fixed coordinate systemrdquo Scaled by A-X separation
Molecular constants of iso-propoxy in cm-1
27161 27162 27163 27164 27165 27166 27167 27168
frequency (cm-1)
simulation
expt
R(1)
R(4)
R(0)
R(2)
R(3)
Q-branch
P(4)
P(1)P(2)
P(3)
271654 271656 271658 271660 271662
frequency (cm-1)
simulation
expt
Iso-propoxy
(2)
ˆ ˆ 2
a a
aa
X A
X L A X AL A c c
E E
y(a)
z
x
b
c
transition typesabc=001
271618 271620 271622 271624 271626 271628
frequency (cm-1)
simulation
expt
ˆA A A AaLX A
270845 270850 270855 270860 270865 270870 270875 270880 270885 frequency (cm-1)
simulation
expt
a Geometry optimized at the UHF6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of T 2-butoxy in GHz
T conformer of 2-butoxy
transition typesabc=203
A XE =68(10) cm-1 55(10) cm-1
270540 270545 270550 270555 270560 270565 270570
frequency (cm-1)
simulation
expt
267525 267530 267535 267540 267545 267550 267555 267560
frequency (cm-1)
simulation
expt
Cyclohexoxy
a Geometry optimized at the B3LYP6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of cyclohexoxy in GHz
abc=100abc=010
BX transition to arsquo vibronic level (origin band)
BX transition to ardquo vibronic level BA transition to arsquo vibronic level
273790 273795 273800 273805 273810 273815 273820 frequency (cm-1)
simulation
expt
Summary and Future work
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Dr Phillip S Thomas
NSF$$$
NSF$$$
Thank you allThank
you all
Miller GroupMiller Group
Acknowledgements
-25 -20 -15 -10 -5 0 5 10 15 20 25
0
100
200
300
400
500
600
700
rela
tive
en
erg
y (c
m-1)
tilt angle of O atom from Cs plane (degree)
-10 -5 0 5 10
0
100
200
300
400
500
600
700
rela
tive
en
erg
y (c
m-1)
tilt angle of O atom from Cs plane (degree)
2 A X
2 A A
in cm-1 ethoxyiso-
propoxy
Calcwo ZPE
wo ΔEPJT (Cs-Cs) +335 -122
w ΔEPJT (C1-Cs) +340 -24
w ZPE +508 -46
Exptdagger +355(10)
-68(10)
(A) (A)E E E
Iso-propoxy vs ethoxy
PJT pseudo-Jahn-Teller
2 A A
2A X
ΔEPJT=98 cm-1
dagger Dispersed Fluorescence Spectroscopy of Primary and Secondary Alkoxy Radicals J Jin I Sioutis G Tarczay S Gopalakrishnan A Bezant T A Miller J Chem Phys 121 11780 (2004)
iso-propoxy ethoxy
ldquogeometry-fixed coordinate systemrdquoldquoorbital-fixed coordinate systemrdquo
Common coordinates for prediction of SR tensor
a Geometry optimized at the B3LYP6-31G level of theory and used to calculate Us
b At the CIS6-31G level of theoryc In the ldquogeometry-fixed coordinate systemrdquo Scaled by A-X separationd In the ldquoorbital-fixed coordinate systemrdquo Scaled by A-X separation
Molecular constants of iso-propoxy in cm-1
27161 27162 27163 27164 27165 27166 27167 27168
frequency (cm-1)
simulation
expt
R(1)
R(4)
R(0)
R(2)
R(3)
Q-branch
P(4)
P(1)P(2)
P(3)
271654 271656 271658 271660 271662
frequency (cm-1)
simulation
expt
Iso-propoxy
(2)
ˆ ˆ 2
a a
aa
X A
X L A X AL A c c
E E
y(a)
z
x
b
c
transition typesabc=001
271618 271620 271622 271624 271626 271628
frequency (cm-1)
simulation
expt
ˆA A A AaLX A
270845 270850 270855 270860 270865 270870 270875 270880 270885 frequency (cm-1)
simulation
expt
a Geometry optimized at the UHF6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of T 2-butoxy in GHz
T conformer of 2-butoxy
transition typesabc=203
A XE =68(10) cm-1 55(10) cm-1
270540 270545 270550 270555 270560 270565 270570
frequency (cm-1)
simulation
expt
267525 267530 267535 267540 267545 267550 267555 267560
frequency (cm-1)
simulation
expt
Cyclohexoxy
a Geometry optimized at the B3LYP6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of cyclohexoxy in GHz
abc=100abc=010
BX transition to arsquo vibronic level (origin band)
BX transition to ardquo vibronic level BA transition to arsquo vibronic level
273790 273795 273800 273805 273810 273815 273820 frequency (cm-1)
simulation
expt
Summary and Future work
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Dr Phillip S Thomas
NSF$$$
NSF$$$
Thank you allThank
you all
Miller GroupMiller Group
Acknowledgements
ldquogeometry-fixed coordinate systemrdquoldquoorbital-fixed coordinate systemrdquo
Common coordinates for prediction of SR tensor
a Geometry optimized at the B3LYP6-31G level of theory and used to calculate Us
b At the CIS6-31G level of theoryc In the ldquogeometry-fixed coordinate systemrdquo Scaled by A-X separationd In the ldquoorbital-fixed coordinate systemrdquo Scaled by A-X separation
Molecular constants of iso-propoxy in cm-1
27161 27162 27163 27164 27165 27166 27167 27168
frequency (cm-1)
simulation
expt
R(1)
R(4)
R(0)
R(2)
R(3)
Q-branch
P(4)
P(1)P(2)
P(3)
271654 271656 271658 271660 271662
frequency (cm-1)
simulation
expt
Iso-propoxy
(2)
ˆ ˆ 2
a a
aa
X A
X L A X AL A c c
E E
y(a)
z
x
b
c
transition typesabc=001
271618 271620 271622 271624 271626 271628
frequency (cm-1)
simulation
expt
ˆA A A AaLX A
270845 270850 270855 270860 270865 270870 270875 270880 270885 frequency (cm-1)
simulation
expt
a Geometry optimized at the UHF6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of T 2-butoxy in GHz
T conformer of 2-butoxy
transition typesabc=203
A XE =68(10) cm-1 55(10) cm-1
270540 270545 270550 270555 270560 270565 270570
frequency (cm-1)
simulation
expt
267525 267530 267535 267540 267545 267550 267555 267560
frequency (cm-1)
simulation
expt
Cyclohexoxy
a Geometry optimized at the B3LYP6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of cyclohexoxy in GHz
abc=100abc=010
BX transition to arsquo vibronic level (origin band)
BX transition to ardquo vibronic level BA transition to arsquo vibronic level
273790 273795 273800 273805 273810 273815 273820 frequency (cm-1)
simulation
expt
Summary and Future work
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Dr Phillip S Thomas
NSF$$$
NSF$$$
Thank you allThank
you all
Miller GroupMiller Group
Acknowledgements
a Geometry optimized at the B3LYP6-31G level of theory and used to calculate Us
b At the CIS6-31G level of theoryc In the ldquogeometry-fixed coordinate systemrdquo Scaled by A-X separationd In the ldquoorbital-fixed coordinate systemrdquo Scaled by A-X separation
Molecular constants of iso-propoxy in cm-1
27161 27162 27163 27164 27165 27166 27167 27168
frequency (cm-1)
simulation
expt
R(1)
R(4)
R(0)
R(2)
R(3)
Q-branch
P(4)
P(1)P(2)
P(3)
271654 271656 271658 271660 271662
frequency (cm-1)
simulation
expt
Iso-propoxy
(2)
ˆ ˆ 2
a a
aa
X A
X L A X AL A c c
E E
y(a)
z
x
b
c
transition typesabc=001
271618 271620 271622 271624 271626 271628
frequency (cm-1)
simulation
expt
ˆA A A AaLX A
270845 270850 270855 270860 270865 270870 270875 270880 270885 frequency (cm-1)
simulation
expt
a Geometry optimized at the UHF6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of T 2-butoxy in GHz
T conformer of 2-butoxy
transition typesabc=203
A XE =68(10) cm-1 55(10) cm-1
270540 270545 270550 270555 270560 270565 270570
frequency (cm-1)
simulation
expt
267525 267530 267535 267540 267545 267550 267555 267560
frequency (cm-1)
simulation
expt
Cyclohexoxy
a Geometry optimized at the B3LYP6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of cyclohexoxy in GHz
abc=100abc=010
BX transition to arsquo vibronic level (origin band)
BX transition to ardquo vibronic level BA transition to arsquo vibronic level
273790 273795 273800 273805 273810 273815 273820 frequency (cm-1)
simulation
expt
Summary and Future work
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Dr Phillip S Thomas
NSF$$$
NSF$$$
Thank you allThank
you all
Miller GroupMiller Group
Acknowledgements
270845 270850 270855 270860 270865 270870 270875 270880 270885 frequency (cm-1)
simulation
expt
a Geometry optimized at the UHF6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of T 2-butoxy in GHz
T conformer of 2-butoxy
transition typesabc=203
A XE =68(10) cm-1 55(10) cm-1
270540 270545 270550 270555 270560 270565 270570
frequency (cm-1)
simulation
expt
267525 267530 267535 267540 267545 267550 267555 267560
frequency (cm-1)
simulation
expt
Cyclohexoxy
a Geometry optimized at the B3LYP6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of cyclohexoxy in GHz
abc=100abc=010
BX transition to arsquo vibronic level (origin band)
BX transition to ardquo vibronic level BA transition to arsquo vibronic level
273790 273795 273800 273805 273810 273815 273820 frequency (cm-1)
simulation
expt
Summary and Future work
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Dr Phillip S Thomas
NSF$$$
NSF$$$
Thank you allThank
you all
Miller GroupMiller Group
Acknowledgements
270540 270545 270550 270555 270560 270565 270570
frequency (cm-1)
simulation
expt
267525 267530 267535 267540 267545 267550 267555 267560
frequency (cm-1)
simulation
expt
Cyclohexoxy
a Geometry optimized at the B3LYP6-31+G level of theoryb At the CIS6-31+G level of theory
Molecular constants of cyclohexoxy in GHz
abc=100abc=010
BX transition to arsquo vibronic level (origin band)
BX transition to ardquo vibronic level BA transition to arsquo vibronic level
273790 273795 273800 273805 273810 273815 273820 frequency (cm-1)
simulation
expt
Summary and Future work
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Dr Phillip S Thomas
NSF$$$
NSF$$$
Thank you allThank
you all
Miller GroupMiller Group
Acknowledgements
Summary and Future work
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Explanation to perturbed transitions and anomalous line intensities in the spectra of cyclohexoxy and T 2-butoxy
Physical mechanism of spin-rotation constants for nearly degenerate electronic states
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Spin-rotation tensor of iso-propoxy predicted in an ldquoorbital-fixed coordinate systemrdquo using ethoxy as a reference molecule
Spin-rotation tensors of T 2-butoxy and cyclohexoxy predicted based on the experimental result of 2-propoxy
Hi-resolution LIF spectra of iso-propoxy T 2-butoxy and cyclohexoxy simulated using the ab initio calculated rotational constants and predicted spin-rotation constants
Transition types determined experimentally confirms the symmetry of electronic states predicted by ab initio calculations
Dr Phillip S Thomas
NSF$$$
NSF$$$
Thank you allThank
you all
Miller GroupMiller Group
Acknowledgements
Dr Phillip S Thomas
NSF$$$
NSF$$$
Thank you allThank
you all
Miller GroupMiller Group
Acknowledgements
