x ray scattering
TRANSCRIPT
X-RAY SCATTERINGFROM ATOMS TO COMPLEX SYSTEMS
Giulio Ungaretti-EXPERIMENTAL X-RAY PHYSICS EXAM -19/7/2013
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Outline
• Simple models
• Adding complexities
• Real life examples
Slides and blackboard
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Atomic scattering
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f 0(Q) =
Z⇢(r)iQ·rd3r
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Molecular scattering
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f
mol(Q) =X
j
f
j
(r)eiQ·rj
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Molecular scattering II
and, more generally:
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ISAXS(Q) / �⇢2P (Q)S(Q)even more:
ISAXS(Q) / �⇢2P (Q)
I(Q) = Nf(Q)2 + f(Q)2X
n
Z
V ol
(⇢(rn
� rm
)� ⇢average
)eiQ·(rn�rm)dV +
| {z }short range
+ f(Q)2X
n
Z
V ol
⇢average
eiQ·(rn�rm)dV
| {z }SAXS
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Adding complexities
• Poly disperse systems• Complex structures• Dynamical diffraction
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Real life examples I: kr scattering
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Real life examples II: CF4 molecule
Unexpected attenuation !!!!!! explian alluminum shit
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Real life examples III: SAXS(ish)-milk fat
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Real life examples III: WAXS milk fat
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Conclusions
• Powerful structural tool
• Can use simple models
• Versatile method
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