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Materials Science Beamline
OSU, Columbus, June 21-25, 2010
SOFT X-RAY SPECTROSCOPY SOFT X-RAY SPECTROSCOPY OF GLYCYL-GLYCINE OF GLYCYL-GLYCINE
ADSORBED ON Cu(110) ADSORBED ON Cu(110) SURFACESURFACE
Sincrotrone Trieste, Sincrotrone Trieste, Basovizza (Trieste), ItalyBasovizza (Trieste), Italy
Victor LyamayevVictor Lyamayev
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
Biomolecule-metal interfaceBiomolecule-metal interface
Fundamental for many Fundamental for many
fieldsfieldsBio sensors, biocompatibility of implantsBio sensors, biocompatibility of implants
Origin of lifeOrigin of life
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
Materials Science Beamline
Why synchrotron Why synchrotron radiation?radiation?• broad energy rangebroad energy range ((2222--8800 eV)00 eV) www.elettra.trieste.itwww.elettra.trieste.it
• high resolving powerhigh resolving power (2000-4000)(2000-4000)
• high high fluxflux (3x10(3x1088-3x10-3x1010 10 photons/s)photons/s)
• linearly polarized linearly polarized (>90%)(>90%)
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
X-ray PX-ray Photoehotoelectron lectron SSpecpectroscopy (XPS)troscopy (XPS)
XPS peaks are shifted due to different chemical state
of the atom (“chemical shift”)
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
Near Edge X-ray Absorption Near Edge X-ray Absorption Fine Structure (NEXAFS)Fine Structure (NEXAFS)
Probing empty MOProbing empty MO
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
DFT model of Gly-Glyon the Cu(110) surface
Density Functional Theory Density Functional Theory (DFT)(DFT)
Glycyl-Glycine (Gly-Gly)
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
Calculated adsorption geometries of Gly-Gly on Cu(110)
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
C 1s XPS spectra: experiment (points),theory (solid lines)
Inte
nsity
(ar
b. u
nits
)
294 292 290 288 286 284 282
Binding energy (eV)
C 1s
1.4 ML
1 ML
AN2
ZW2
ZW4
AN4297 296 295 294 293 292 291 290
Binding energy (eV)
Gas phase
Increased due tozwitterions ->
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
N 1s XPS spectra: experiment (points),theory (solid lines)
Inte
nsity
(ar
b. u
nits
)
406 404 402 400 398 396
Binding energy (eV)
1.4 ML
1 ML
N(1)H+
-CON(2)H-
N(1)-H...Cu
51 %3
N(1)H2
9 %
N 1s
N(1)H2-CON(2)H-91%
49 %
ZW2
AN2
ZW4
AN4408 407 406 405 404
Binding energy (eV)
Gas phase
50% ofzwitterions ->
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
O 1s XPS spectra: experiment (points),theory (solid lines)
Inte
nsity
(ar
b. u
nits
)
538 536 534 532 530 528 526Binding energy (eV)
1.4 ML
1 ML
O 1s
ZW2
AN2
ZW4
AN4542 541 540 539 538 537 536 535
Binding energy (eV)
Gas phase
0.1 eV broader ->
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
Inte
nsity
(ar
b. u
nits
)
425420415410405400395Photon energy (eV)
N
GI
NI
400.05
401.7
405.8
N K-edge NEXAFS spectra of 1 ML of Gly-Glymeasured at grazing (GI) and normal (NI) incidence
N-H bond of CONH ->
NCONH->
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
O K-edge NEXAFS spectra of 1 ML of Gly-Glymeasured at grazing (GI) and normal (NI) incidence
Inte
nsity
(ar
b. u
nits
)
560555550545540535530Photon energy (eV)
s_O_NI_HCflash420K_aver_sub s_O_GI_HCflash420K_aver_sub
O
GI
NI
532.7
535.7
545.0
OCONH + OCOO ->
OCOO…Cu ->
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
Proposed adsorption geometries of 1 ML of Gly-Gly
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
C 1s XPS spectra of 0.4 ML of Gly-Gly:experiment (points), theory (solid lines)
Inte
nsity
(ar
b. u
nits
)
292 290 288 286 284 282Binding energy (eV)
C(4)NC(2)N
-C(3)ONH-
C(1)OO-
C 1s
AN2a
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
N 1s XPS spectra of 0.4 ML of Gly-Gly:experiment (points), theory (solid lines)
Inte
nsity
(ar
b. u
nits
)
406 404 402 400 398 396 394Binding energy (eV)
-CON(2)H- N(1)-H...Cu
N 1s
AN2a
<- due to interaction via H
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
O 1s XPS spectra of 0.4 ML of Gly-Gly:experiment (points), theory (solid lines)
Inte
nsity
(ar
b. u
nits
)
536 534 532 530 528 526Binding energy (eV)
O 1s
AN2a
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
N and O K-edge NEXAFS spectra of 0.4 ML of Gly-Glymeasured at grazing (GI) and normal (NI) incidence
Inte
nsity
(ar
b. u
nits
)560555550545540535530
Photon energy (eV)
O532.7
GI
NI
535.7
545.0
Inte
nsity
(ar
b. u
nits
)
425420415410405400395
Photon energy (eV)
NI
GI
N400.05
401.7
405.8413.0
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
Proposed adsorption geometries of 0.4 ML of Gly-Gly
Materials Science Beamline
OSU, Columbus, June 21-25, 2010
I’d like I’d like to to thank…thank…
……and thank you for your attention.and thank you for your attention.
Vitaliy FeyerVitaliy Feyer
Oksana PlekanOksana Plekan
Kevin C. PrinceKevin C. Prince
Materials Science Beamline at Materials Science Beamline at Elettra,Elettra,
Trieste, Trieste, ItalyItaly
V. CarravettaV. Carravetta Institute of Chemical Physical Institute of Chemical Physical Processes, Pisa, ItalyProcesses, Pisa, Italy