x-ray absorption spectroscopy - cfel · core valence overlap [5 ev] core spin-orbit coupling [15...
TRANSCRIPT
![Page 1: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/1.jpg)
www.anorg.chem.uu.nl/people/staff/FrankdeGroot/
X-ray absorption spectroscopy
![Page 2: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/2.jpg)
Frank de Groot
PhD: solid state chemistry U Nijmegen (91)
Post-doc: LURE, Orsay (93-94)
Post-doc: solid state physics U Groningen (95-98)
U Utrecht since 1999
Synchrotron and theoretical spectroscopy
of catalytic nanomaterials
(inorganic chemistry and catalysis)
www.anorg.chem.uu.nl/people/staff/FrankdeGroot/
X-ray absorption spectroscopy
![Page 3: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/3.jpg)
![Page 4: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/4.jpg)
Interaction of x-rays with matter
• XAFS studies photoelectric absorption
• Elastic scattering (Thompson)
• Inelastic scattering
• (Compton)100 1k 10k 100k 1M
1
10
100
Photonuclear
Electron-
positron
Photoelectric
Thompson
Compton
Inte
nsity (
log
)
Energy (eV)
Mn
Interaction of x-rays with matter
![Page 5: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/5.jpg)
X-ray absorption of an atomXAS of an atom
![Page 6: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/6.jpg)
X-ray absorption of a solidXAS of a solid
![Page 7: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/7.jpg)
X-ray absorption of a solidXAS of a solid
![Page 8: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/8.jpg)
Fe 4p -
Fe 3d 0
O 2p 5
O 2s 20
Fe 3p 50
Fe 3s 85
O 1s 530
Fe 2p 700
Fe 2s 800
Fe 1s 7115
X-ray absorption of a solidXAS of a solid
![Page 9: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/9.jpg)
X-ray absorption of a solidXAS of a solid
![Page 10: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/10.jpg)
if EEiffXAS TI
2
1~
Excitation of core electrons to empty states.
Spectrum given by the Fermi Golden Rule
X-ray absorption and X-ray photoemissionXAS and XPS
![Page 11: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/11.jpg)
X-ray absorption and X-ray photoemissionXAS and XPS
![Page 12: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/12.jpg)
X-ray absorption and X-ray photoemissionXAS and XPS
![Page 13: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/13.jpg)
if EEiffXAS reI
2
ˆ~
Excitations of
core electrons
to empty states
The XAS spectrum
is given by the
Fermi Golden Rule
X-ray absorption spectroscopy
![Page 14: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/14.jpg)
Excitations of
core electrons
to empty states
The XAS spectrum
is given by the
Fermi Golden Rule
symmetrysiteXAS MI ,2~
X-ray Absorption Spectroscopy
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Density of States
(DOS) is the integral
over k-space of the
band structure.
Core states have no
dispersion.
XAS preserves
momentum (k)
X-ray Absorption Spectroscopy
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2p
2s
Phys. Rev. B.40, 5715 (1989)
X-ray Absorption Spectroscopy
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X-ray Absorption Spectroscopy
Phys. Rev. B.40, 5715 (1989); 48, 2074 (1993)
oxygen 1s > p DOS
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Electronic Structure; TiO2
Phys. Rev. B. 40, 5715 (1989); 48, 2074 (1993)
Density of States of TiO2
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Electronic Structure: TiO2
Phys. Rev. B. 40, 5715 (1989); 48, 2074 (1993)
Density of States of TiO2
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• Final State Rule:
Spectral shape of XAS
looks like final state
DOS
Phys. Rev. B.
41, 11899 (1991)
TiSi2
• Initial State Rule:
Intensity of XAS is given
by the initial state
X-ray absorption: core hole effectXAS: core hole effect
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Excitation of core electrons to empty states.
Spectrum identifies with the
empty Density of States
Works well for K edges (1s)
Calculate with DFT
(LDA+U, DMFT, BSE)
X-ray absorptionX-ray Absorption Spectroscopy
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2p
2s
Metal 1s XAS
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2p
2s
Metal 1s XAS
Juhin et al., Phys. Rev. B. 78, 195103 (2008)
Cr3+ in MgAl2O4
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3dN 4p0
edge1s13dN4p1
Pre-edges structures in 1s XAS
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3dN 4p0 1s13dN+14p0 pre-edge
edge1s13dN4p1
Pre-edges structures in 1s XAS
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CoIII(acac)
Pre-edge and edge
low-spin CoIII
3d6 [1A1]
T2g full
Eg empty
Pre-edges structures in 1s XAS
![Page 27: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/27.jpg)
7710 7715 7720 7725
0
1
edge
?pre-
edge
Energy (eV)
Co K edge of LiCoO2
low-spin CoIII
3d6 [1A1]
T2g full
Eg empty
K pre-edge of TM oxides (LiCoO2)Pre-edges structures in 1s XAS
![Page 28: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/28.jpg)
Excitation of core electrons to empty states.
Spectrum identifies with the
empty Density of States
Works well for K edgesMetal K edges: quadrupole 1s3d transitions
X-ray absorptionX-ray absorption spectroscopy
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Fermi Golden Rule:
IXAS = |<f|dipole| i>|2 [E=0]
Single electron (excitation) approximation:
IXAS = |<empty|dipole| core>|2
X-ray absorptionX-ray absorption spectroscopy
![Page 30: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/30.jpg)
Quiz: Calculate the 2p XAS spectrum of Fe atom
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Fermi Golden Rule:
IXAS = |<f|dipole| i>|2 [E=0]
i =1s2 2s2 2p6 3s2 3p6 4s2 3d6
f =1s2 2s2 2p5 3s2 3p6 4s2 3d7
i =2p6 3d6
f =2p5 3d7
X-ray absorption of an Fe atomXAS of an iron atom
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Fermi Golden Rule:
IXAS = |<f|dipole| i>|2 [E=0]
Single electron (excitation) approximation:
IXAS = |<empty|dipole| core>|2
X-ray absorption
i =2p6 3d6
f =2p5 3d7
core = 2p
empty = 3d
Neglect 2p-3d interactions (in the final state)
XAS of an iron atom
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Multiplet Effects in XAS
2p3/2
2p1/2
Overlap of core and valence wave functions
3d
<2p3d|1/r|2p3d>
XAS of an iron atom
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Multiplet Effects in XAS
2p3/2
2p1/2
Direct 2p3d Coulomb interaction (=
core hole potential) is screened in
molecules and solids.
Higher order terms (Coulomb and
exchange) are NOT screened in
molecules and solids
3d
<2p3d|1/r|2p3d>
XAS of atoms and solids
![Page 35: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/35.jpg)
Multiplet Effects in XAS
2p3/2
2p1/2
Single Particle model breaks down
3d
PRB 42, 5459 (1990)
<2p3d|1/r|2p3d>
XAS of atoms and solids
![Page 36: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/36.jpg)
Single Particle:
1s edges(WIEN, FEFF, PARATEC,
…..)
Multiplets:
2p, 3s, 3p edges
(TT-MULTIPLETS)
XASXAS of molecules and solids
![Page 37: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/37.jpg)
Single Particle:
1s edges(WIEN, FEFF, ORCA,
PWSCF, etc.)
Multiplets:
2p, 3s, 3p edges
(TT-MULTIPLETS)
No Unified
Interpretation!
XASXAS of molecules and solids
![Page 38: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/38.jpg)
Used for the analysis of XAS, EELS,
Photoemission, Auger, XES,
ATOMIC PHYSICS
GROUP THEORY
MODEL HAMILTONIANS
Charge transfer multiplet program
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CTM4XAS program
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CTM4XAS version 5.2CTM4XAS program
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N
iii
pairs
re
N
rZe
N
m
pslrH
iji
i )(222
2
Atomic Multiplet Theory
=E
• Kinetic Energy
• Nuclear Energy
• Electron-electron interaction
• Spin-orbit coupling
Atomic Multiplet Theory
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N
iii
pairs
re
N
rZe
N
m
pslrH
iji
i )(222
2X X
=E
• Kinetic Energy
• Nuclear Energy
• Electron-electron interaction
• Spin-orbit coupling
Atomic Multiplet Theory
![Page 43: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/43.jpg)
N
iii
pairs
re
ATOM slrHij
)(2
k
k
k
k
k
kJ
S
re
J
S GgFfLL 1212 ||12
2
Electron Correlation of Valence States [5 eV]
Valence Spin-orbit coupling [0.1 eV]
Atomic Multiplet Theory (ground state)
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N
iii
pairs
re
ATOM slrHij
)(2
k
k
k
k
k
kJ
S
re
J
S GgFfLL 1212 ||12
2
Core Valence Overlap [5 eV]
Core Spin-orbit coupling [15 eV]
Atomic Multiplet Theory (core hole)
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2p XAS of ScF3
• Ground state is 3d0
• Dipole transition 3d02p53d1
• Dipole selection rules:
S=1 and L=±1
• Core hole spin-orbit coupling large
• L and S are no good quantum numbers
J=±1 or 0
(J=J0)
2p XAS of a Ca atom
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Term Symbols
• Term Symbol 2S+1LJ
• L=0,1,2,3,4 > S, P, D, F, G
• LS quantum numbers not useful for XAS due to large
spin-orbit coupling of the core hole.
• Use only J quantum numbers
• Degeneracy of each J-state: 2J+1
Term symbols
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Term symbols of a 1s electron
• S=1/2, L=0
J=1/2 2S1/2
Term symbols of a 3d electron
• S=1/2, L=2
J=3/2 or J=5/2 2D3/2 or 2D5/2
Term Symbols Term symbols
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Term Symbols
2p3d-configuration (6x10 = 60 states)
all combinations are possible:
In short: 2P2D = 1,3P,D,F
Add J-quantum numbers:1P1,
1D2, 1F3
+ 3P0, 3P1,
3P2
+ 3D1, 3D2,
3D3,
+ 3F2, 3F3,
3F4,
Term symbols
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2p XAS of ScF3
Ground state is 3d0: symmetry: 1S0
Dipole transition 3d02p53d1
Selection rule: J=±1 or 0 (and J=J’0)
J’=1
2p XAS of a Ca atom
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• Term symbols of a 2p53d1 configuration
3P01P1
3P1, 3P2
3D11D2
3D23D3
3F21F3
3F33F4
[1 3 4 3 1]
1 3x3 4x5 3x7 1x9
Term Symbols
Ground state: 3d0: L=S=J=0 1S0
Selection rule: Final state must have J’=1
2p XAS of a Ca atom
![Page 51: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/51.jpg)
2p XAS of a Ca atom
Ground state is 3d0
2p XAS of a Ca atom
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t2g states
Crystal Field Effects
eg states
2p XAS of ScF3: crystal fields
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Octahedral crystal field splitting
metal ion
in free space
in symmetrical field
t2g
yz xz xy
eg
in octahedral ligand field
x2-y2 z2
x2-y2 yz z2 xz xy
2p XAS of ScF3: crystal fields
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Comparison with Experiment2p XAS of ScF3
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CTM4XAS version 5.2Calculations with CTM4XAS
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2p XAS of transition metal ions
Ground state is 3dN: determine symmetry
Hunds rule: High-spin ground states
max S, max L, max J
Effect of crystal field splitting
High spin or low spin
Effect of 3d spin-orbit coupling
Charge transfer effects
2p XAS of transition metal ions
![Page 57: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/57.jpg)
Effect of 10Dq on XAS:3dN2p XAS of VF3
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High-spin or Low-spin
10Dq > 3J
(d4 and d5)
10Dq > 2J
(d6 and d7)
High-spin or low-spin
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High-spin: 10Dq = 1.2
Low-spin: 10Dq = 3.0
High-spin or Low-spinHigh-spin or low-spin
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High-spin or Low-spinHigh-spin or low-spin
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3d spin-orbit coupling3d spin-orbit coupling
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3d spin-orbit coupling3d spin-orbit coupling
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Ground state of a transition metal system
3dN at every site
Charge fluctations
Charge Transfer EffectsCharge transfer effects
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Hubbard U for a 3d8 ground state:
U= E(3d7) + E(3d9) – E(3d8) – E(3d8)
Ligand-to-Metal Charge Transfer (LMCT):
= E(3d9L) – E(3d8)
Charge Transfer EffectsCharge transfer effects
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3d6L
• Transition metal oxide: Ground state: 3d5 + 3d6L
• Energy of 3d6L: Charge transfer energy
XAS
2p53d7L
+U-Q
2p53d6
3d5
2p53d6L
XPS
2p53d5
-Q
Ground State
Charge transfer effects in XAS and XPSCharge transfer effects
![Page 66: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/66.jpg)
Charge Transfer effects
• High valent oxides (Cu3+)
• Systems with π-bonds
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=10
NiO
La2Li½Cu½O4
=-5
=5
=0
=-10
3d8 + 3d9L
J. Elec. Spec.67, 529 (1994)
Charge Transfer Effects in XASCharge Transfer effects in XAS
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=10
NiO
La2Li½Cu½O4
30% 3d8
1A1
30% 3d8
3A2=-5
=5
=0
=-10
3d8 + 3d9L
Chem. Phys. Lett. 297, 321 (1998)
Charge Transfer Effects in XASCharge Transfer effects in XAS
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3d6L
3d5
2p53d7L
2p53d6+U-Q
FeIII: Ground state: 3d5 + 3d6L
C NM
filled
d-orbital
empty *-orbital
M C N
filled -
orbitalempty d or p
orbital
(i) -
C?C?N distance
C NM
filled
d-orbital
empty *-orbital
M C N
filled -
orbitalempty d or p
orbital
(i)
C?
C NM
filled
d-orbital
empty *-orbital
M C N
filled -
orbitalempty d or p
orbital
(i) -
C?C?N distance
C NM
filled
d-orbital
empty *-orbital
M C N
filled -
orbitalempty d or p
orbital
(i)
C?
(i) donation (ii) back-donation
empty
d-orbital
filled
orbital
LMCT and MLCT: - bonding
with Ed Solomon (Stanford) JACS 125, 12894 (2003),
JACS 128, 10442 (2006), JACS 129, 113 (2007)
![Page 70: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/70.jpg)
3d4L
3d6L
3d5
FeIII: Ground state: 3d5 + 3d6L + 3d4L
2p53d5L
2p53d7L
2p53d6
+U-Q - 2
-U+Q + 2
with Ed Solomon (Stanford) JACS 125, 12894 (2003),
JACS 128, 10442 (2006), JACS 129, 113 (2007)
LMCT and MLCT: - bonding
![Page 71: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/71.jpg)
-2
0
2
4
6
8
10
700 705 710 715 720 725 730
Energy (eV)
No
rmali
zed
Ab
so
rpti
on
Fit X
Series2
FeIII(tacn)2
FeIII(CN)6
with Ed Solomon (Stanford) JACS 125, 12894 (2003),
JACS 128, 10442 (2006), JACS 129, 113 (2007)
LMCT and MLCT: - bonding
![Page 72: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/72.jpg)
Huse et al. JACS 132, 6809 (2010); JPCL 2, 880 (2011)
Time resolved XAS
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Single Particle:
1s edges
(DFT + core hole (+U))
2-particle:
(TDDFT, BSE)
+ L edges of 3d0
Multiplets:
2p, 3s, 3p edges
(CTM4XAS)
XAS: multiplet effects
![Page 74: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/74.jpg)
• Time: excited states in fs/ps/ns range
• Pressure: 1 bar/500 ºC flowing gas
• Space: 0.5 nm (STEM), 20 nm (STXM)
• Element specific
• Low concentrations (0.01-0.1 wt%)
Why X-ray absorption?
• local electronic & magnetic structure
• valence, spin-state, symmetry
• hybridization, MO energies / density of states
• crystal field, charge transfer, spin-orbit, moments
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Quiz: Calculate the 2p XAS spectrum of Fe atom
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Quiz: Calculate the 2p XAS of NiF2 and NiCl2
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X-MCDMagnetic circular dichroism
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Quiz: Calculate the X-MCD of ferromagnetic Ni2+
Arrio et al. JPC 100, 4679 (1996)
[NiIICrIII(CN)6]1-
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3d6L
• Transition metal oxide: Ground state: 3d5 + 3d6L
• Energy of 3d6L: Charge transfer energy
XAS
2p53d7L
+U-Q
2p53d6
3d5
2p53d6L
XPS
2p53d5
-Q
Ground State
Charge transfer effects in XAS and XPSCharge transfer effects
![Page 80: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/80.jpg)
Quiz: Calculate the 2p XPS of NiF2 and NiCl2
![Page 81: X-ray absorption spectroscopy - CFEL · Core Valence Overlap [5 eV] Core Spin-orbit coupling [15 eV] Atomic Multiplet Theory (core hole) 2p XAS of ScF 3 •Ground state is 3d0 •Dipole](https://reader034.vdocuments.net/reader034/viewer/2022050121/5f510979c9172c1fc5220c35/html5/thumbnails/81.jpg)
XASXAS experiments
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2p 3/22p 1/2
2s
1s
fluorescent
radiation
2p 3/22p 1/2
2s
1s
Fluorescence Auger
Core Hole DecayXAS experiments: using the core hole decay
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XASXAS experiments
Quiz: How to measure XAS of a solid
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XASXAS experiments
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