XPDFA Dedicated X-ray PDF BeamlinePhase III Beamline Proposal

DISCO Presentation 24 February 2011

Pair Distribution Function (PDF)

• Quantitative experimental probeof local structure in materials

• Fourier transform of powder dif-fraction pattern; gives histogramof interatomic separations

• Quantifies “true” bond lengths,coordination number, dynamics

• Resolution determined by Qmaxso requires high-energy X-rays

• Applicable to crystals, nanocrys-tals, amorphous materials, liquids

Catalysis

• “Differential PDF” allowsstructural characterisation ofe.g. nanoparticulate catalystsmounted on solid substrates

• Rapid PDF analysis allows for insitu measurements of localstructure changes in real timeduring catalytic processes

• Model-independent observationof interatomic distances;cf EXAFS, NMR

Pt–Pt Differential PDF

TiO2 substrate

NanoparticulatePt catalyst

Chupas, Chapman, Chen and Grey, Catalysis Today 145, 13 (2009)

• Structural characterisation ofamorphous and nanocrystallinedrug materials

• “Fingerprinting” for IP applications• Determination of impact of

processing on solid form ofamorphous products

• Tracking of structural changeswith time, temperature and%R.H.

• Characterisation of crystallisationpathways in amorphousbiomaterials; e.g. a-Ca3(PO4)2

Health and Pharmaceutics

Billinge et al, CrystEngComm 12, 1366 (2010)

Crystalline form 1

Crystalline form 2

Amorphous form

Energy

• Gas sorption dynamics andbinding site preferences inporous materials

• CO2 capture in ionic liquids• In operando measurement of ion

transport mechanisms in batterymaterials

• Parametric studies undervariable temperature, pressure,gas flow, charge/discharge

Digital Economy

• Structure–electronic propertyrelationships in amorphoustransparent conducting oxides

• Local structure and dynamics inthin-film ferroelectrics

• Nanoscale disorder in dilutemagnetic semiconductors forspintronics

• Amorphous–crystalline transitionsin phase change chalcogenidesfor data storage (e.g. DVD-RAM)Matsunaga et al, Nature Materials 10, 129 (2011)

GST Crystal PDF

GST Amorphous PDF

XPDF Beamline Design

• Sidestation to I-15 with high-energy beam profile(superconducting multipole wiggler)

• Cost-effective design maximises scientific potential of existinginfrastructure

• Range of sample environments; 2D detector for rapid and robustdata acquisition

XPDF Industrial Supporters