Powder Diffraction - Spallation Neutron Source

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$Single Crystal Diffraction - Spallation Neutron Source$

Space Groups Not all combinations of symmetry and lattice types are compatible – Example: mirror plane perpendicular to a non-orthogonal pair of axes ∆ There are only 230 unique ways to combine symmetry elements for a 3D lattice: 230 space groups ∆ Space groups are tabulated in The International Tables of Crystallography, Volume A I recommend Space Groups for Solid State Scientists by G. Burns and A. M. Glazer as a good place to learn about space groups and s.g. properties ∆ 64
Fractional coordinates Atom locations are measured in fractions of the unit cell edges – Note atom is at x=0.45,y=0.25 ∆ This notation allows for simple description of symmetry operations: (x,y,z) --> (1+x, y, z) [translation on x] (x,y,z) --> (1/2+x, 1/2+y, 1/2+z) [centering] (x,y,z) --> (-x, -y, -z) [center of symmetry @ origin] In crystallographic notation x=0.45(3) means that there is a standard uncertainty of 0.03 on the value for x of 0.45 Equivalently, there is a 95% chance that x is between 0.39 and 0.51 (2) 65
Page 1 and 2:
A Very Abbreviated Introduction to
Page 3 and 4:
Where to go for more… There are m
Page 5 and 6:
Basic Crystallography 5
Page 7 and 8:
Lattice planes General Indices: la
Page 9 and 10:
Diffraction from single crystals D
Page 11 and 12:
Powder Diffraction 11
Page 13 and 14: Bragg cones in powder diffraction S
Page 15 and 16: Coherent Atomic Scattering Power (d
Page 18 and 19: Resonant Conditions X-rays X-ray fo
Page 20 and 21: Measuring powder diffraction Angul
Page 22 and 23: Highest resolution requires high co
Page 24 and 25: Powder Instruments: Constant Wavele
Page 26 and 27: Time of Flight Diffraction Time of
Page 28 and 29: Neutron Powder Diffraction with Spa
Page 30 and 31: Materials effects on Powder Diffrac
Page 32 and 33: Crystallite Size Broadening d*=cons
Page 34 and 35: Microstrain Broadening See GSAS Man
Page 36 and 37: Anisotropic strain broadening terms
Page 38 and 39: Fitting of Powder Diffraction Data
Page 40 and 41: Fitting crystallographic data -- wh
Page 42 and 43: Hugo Rietveld’s technique Hugo R
Page 44 and 45: Hugo Rietveld in the Petten Reactor
Page 46 and 47: Hugo Rietveld’s other breakthroug
Page 48 and 49: What sort of data are needed for Ri
Page 50 and 51: Limitations of Rietveld Rietveld c
Page 52 and 53: Approaches to Profile Models Three
Page 54 and 55: Voigt vs. Pseudo-Voigt A Gaussian c
Page 56 and 57: Axial Divergence (Low Angle Asymmet
Page 58 and 59: Sample Displacement & Transparency
Page 60 and 61: The Unit Cell The unit cell descri
Page 62 and 63: Lattice Types Centering causes latt
Page 66: Reciprocal Lattice To simplify mat
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Powder Diffraction - Spallation Neutron Source

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