Theoretical Studies of Observable Transitions to Recoupled Pair Bonded States of Sulfur Halide...
26
Theoretical Studies of Observable Transitions to Recoupled Pair Bonded States of Sulfur Halide Compounds Jeff Leiding , D. E. Woon, T. H. Dunning, Jr. University of Illinois SF/SCl, SF 2 /SFCl/SCl 2
-
Upload
amber-childrey -
Category
Documents
-
view
213 -
download
0
Transcript of Theoretical Studies of Observable Transitions to Recoupled Pair Bonded States of Sulfur Halide...
Theoretical Studies of Observable Transitions to Recoupled Pair Bonded
States of Sulfur Halide CompoundsJeff Leiding, D. E. Woon, T. H. Dunning, Jr.
University of Illinois
SF/SCl, SF2/SFCl/SCl2
Motivation for Current Work
SF2: Woon, D. E.; Dunning, T. H., Jr. J. Phys. Chem. A 2009, 113, 7915.SFCl: Leiding, J.; Woon, D. E.; Dunning, T. H., Jr. J. Phys. Chem. A 2011, 115, 329.SCl2: Leiding, J; Woon, D. E.; Dunning, T. H., Jr. J. Phys. Chem. A 2011, 115, 4757.
a4Σ-
X2Πσ*π*π*
Motivation for Current Work
SF2: Woon, D. E.; Dunning, T. H., Jr. J. Phys. Chem. A 2009, 113, 7915.SFCl: Leiding, J.; Woon, D. E.; Dunning, T. H., Jr. J. Phys. Chem. A 2011, 115, 329.SCl2: Leiding, J; Woon, D. E.; Dunning, T. H., Jr. J. Phys. Chem. A 2011, 115, 4757.
a4Σ-
X2Πσ*π*π*
Spin-forbidden
Motivation for Current Work
SF2: Woon, D. E.; Dunning, T. H., Jr. J. Phys. Chem. A 2009, 113, 7915.SFCl: Leiding, J.; Woon, D. E.; Dunning, T. H., Jr. J. Phys. Chem. A 2011, 115, 329.SCl2: Leiding, J; Woon, D. E.; Dunning, T. H., Jr. J. Phys. Chem. A 2011, 115, 4757.
a4Σ-
A2Σ-
X2Πσ*π*π*
Spin-forbidden
Spin-allowed
Methods
•CASSCF/MRCI+Q•aug-cc-pV(5+d)Z for diatomics•aug-cc-pV(Q+d)Z for triatomics•Transform CAS orbitals into GVB orbitals: singly occupied, atom-centered
CASSCF: Complete active space self-consistent fieldMRCI: Multireference configuration interactionGVB: Generalized valence bond
Low-Lying States of SClSCl(a4Σ-)SCl(X2Π)
Low-Lying States of SClSCl(a4Σ-)SCl(X2Π)
Low-Lying States of SClSCl(a4Σ-)SCl(X2Π)
No experimental data for excited states of SCl/SF
Covalent SCl(X2Π) GVB Orbitals
SCl(a4Σ-) GVB Orbitals
Recoupled SCl(2,4Σ-)
GVBL GVBR
re(4Σ-) orbs
2,4Σ- orbs coupled
coupled
MO/GVB
Recoupled SCl(2,4Σ-)
antibonding
GVBL GVBR
re(4Σ-) orbs
2,4Σ- orbs coupled
coupled
MO/GVB
4Σ- : “Recoupled pair bond”
Recoupled SCl(2,4Σ-)
antibonding
GVBL GVBR
re(2Σ-) orbs
re(4Σ-) orbs
2,4Σ- orbs coupled
coupled
coupled
MO/GVB
2Σ- : “Frustrated recoupled pair bond”
4Σ- : “Recoupled pair bond”
Low-Lying Triatomic States
SX(2Π)
SX(2Σ-)
1. Li et al. J. Phys. Chem. A 1998, 102, 7233.2. Colton et al. J. Elec. Spec. Relat. Phenom. 1974, 3, 345.3. Gholivand, K. et al. Phosphorus, Sulfur and Silicon, 1996, 1, 269.
Low-Lying Triatomic States
SX2(1A1)SX(2Π)
SX(2Σ-)
1. Li et al. J. Phys. Chem. A 1998, 102, 7233.2. Colton et al. J. Elec. Spec. Relat. Phenom. 1974, 3, 345.3. Gholivand, K. et al. Phosphorus, Sulfur and Silicon, 1996, 1, 269.
Low-Lying Triatomic States
SX2(1A1)
SX2(1B1)
SF2 singly occupied orbitals
SF2(1B1)
SX(2Π)
SX(2Σ-)
Te, Tv (eV)1. Li et al. J. Phys. Chem. A 1998, 102, 7233.2. Colton et al. J. Elec. Spec. Relat. Phenom. 1974, 3, 345.3. Gholivand, K. et al. Phosphorus, Sulfur and Silicon, 1996, 1, 269.
2.3
Low-Lying Triatomic States
SX2(1A1)
SX2(1B1)
SX2(1A2)SF2 singly occupied orbitals
SF2(1A2)
SF2(1B1)
SX(2Π)
SX(2Σ-)
Te, Tv (eV)1. Li et al. J. Phys. Chem. A 1998, 102, 7233.2. Colton et al. J. Elec. Spec. Relat. Phenom. 1974, 3, 345.3. Gholivand, K. et al. Phosphorus, Sulfur and Silicon, 1996, 1, 269.
2.3
0.7
Low-Lying Triatomic States
SX2(1A1)
SX2(1B1)
SX2(1A2)SF2 singly occupied orbitals
SF2(1A2)
SF2(1B1)
SX(2Π)
SX(2Σ-)
Te, Tv (eV)1. Li et al. J. Phys. Chem. A 1998, 102, 7233.2. Colton et al. J. Elec. Spec. Relat. Phenom. 1974, 3, 345.3. Gholivand, K. et al. Phosphorus, Sulfur and Silicon, 1996, 1, 269.
2.3
0.7
SFCl Bond-Stretch Isomers
F-recoupled
Cl-recoupled
SFCl(A1A″): Minima on same PES
SFCl Bond-Stretch Isomers Singly occupied orbitals
∆E=9.0 kcal/mol
1.594 Å
θ=86.9º2.421 Å
1.912 Å
1.962 Å θ=88.5º
F-recoupled
Cl-recoupled
SFCl(A1A″): Minima on same PES
(PES for a3A″)
SFCl Bond-Stretch Isomers Singly occupied orbitals
∆E=9.0 kcal/mol
1.594 Å
θ=86.9º2.421 Å
1.912 Å
1.962 Å θ=88.5º
We predict observable signature of bond-stretch isomerism due to recoupled-pair bonding:
“1A2” line will split.
F-recoupled
Cl-recoupled
fe=oscillator strengthEnergies (eV)
SFCl(A1A″): Minima on same PES
(PES for a3A″)
Conclusions
1.RPB exhibited in low-lying states of SF/SCl and SF2/SFCl/SCl2
2.Understand excited state behavior via RPB model3.Good agreement of excited state observables with
experiment4.Predictions for excited states of SF/SCl and
SF2/SFCl/SCl25.Possibility of observing electronic signature of
bond-stretch isomers in SFCl via electronic spectroscopy
Acknowledgements• Professor Thom Dunning• Dr. David Woon• Dr. Lina Chen• Dunning Group• Funding: NCSA, Distinguished Chair for Research Excellence in
Chemistry
Low-Lying triatomic states (Te)
SX2(1A1)
SX2(1B1)
SX2(1A2)
Low-Lying triatomic states (Te)
Excitation energies (kcal/mol)
Singlet-Triplet gap (kcal/mol)
52.9
20.3
16.2
SCl2SF2
50.2
14.5
18.513.3
20.0
SX2(1A1)
SX2(1B1)
SX2(1A2)
Relaxed geometries
1A1 geometries
SCl2(1B1) SF2(1B1)
unfavorable
Low-Lying triatomic states (Tv,Te)
Molecule State Method Te Tv
SF2 1B1 Theo 53.0 119.3
1A2 Theo 69.1 82.0
SCl2 1B1 Theo 50.2 78.4
1A2 Theo 70.3 83.3
