When a crystalline sample is illuminated with x-rays, the x-rays are scattered (diffracted) into very specific directions with various intensities. Detectors are used to measure this "diffraction pattern," which is then processed by computers to deduce the arrangement of atoms within the crystal.
Hard x-rays have wavelengths comparable to the distance between atoms. Essentially everything we know about the atomic structure of materials is based on results from x-ray and neutron diffraction. From advanced ceramics to catalysts, from semiconductor technology to the frontiers of medicine, and from new magnetic materials and devices to framework compounds used to sequester radioactive waste, crystallography using hard x-ray diffraction techniques at synchrotron radiation facilities plays a crucial role in our ability to understand and control the world in which we live.
The scattering of x-rays from protein crystals is the most powerful method of determining the three-dimensional structure of large biological molecules (macromolecules). Because macromolecules are large and flexible, their crystals tend to be small, imperfect, and weakly diffracting. In many cases, the intensity, small beam size, and collimation of a synchrotron beam is vital for successful results.
Soft x-ray scattering techniques employ the excitation of electrons in relatively shallow core energy levels (100–2000 eV) to probe the electronic structure and other properties of various kinds of matter. The sample is illuminated with monochromatic soft x-rays, and the scattered photons are detected over a small angular range. In the elastic scattering mode, one measures the speckle diffraction pattern. In the inelastic mode, the scattered photons are passed through a spectrometer and analyzed.
Selected Scattering Highlights
The Importance of Domain Size and Purity in High-Efficiency Organic Solar Cells
Guided Self-Assembly of Gold Thin Films
Central Activator Keeps the Circadian Clock Ticking
Polarized X-Rays Reveal Molecular Alignment in Printed Electronics
Borrowing from Nature to Produce Highly Structured Biomimetic Materials
Hidden Rotational Symmetries in Magnetic Domain Patterns
Resonant Soft X-Ray Scattering of Tri-Block Copolymers
Lensless Imaging of Magnetic Nanostructures
Signal Recognition Particle-Receptor Complex Structure Solved
Structure of DNA-bound FEN1 Reveals Mechanism of Action
Dynein Motor Domain Shows Ring-Shaped Motor, Buttress
Lensless X-Ray Imaging in Reflection
Mineral Deformation at Earth's Core–Mantle Boundary
Inhibiting Individual Notch Receptors Improves Treatment
Two Novel Ultra-Incompressible Materials
Cool Magnetic Molecules
A New Light on Disordered Ensembles
Heterogeneous Morphology Found in Organic Solar Cells
Giant Protease TPP II’s Structure, Mechanism Uncovered
Topoisomerase II Structure Suggests Novel DNA Cleavage Mechanism
The Surprising Appearance of Nanotubular Fullerene D5h(1)-C90
Structure of All-Polymer Solar Cells Impedes Efficiency
Mechanical Behavior of Indium Nanostructures
Lensless Imaging of Whole Biological Cells with Soft X-Rays
A New Route to Nano Self-Assembly
Rotary Firing in Ring-Shaped Protein Explains Unidirectionality
Structures of the Ribosome in Intermediate States of Ratcheting
Proton Channel Orientation in Block-Copolymer Electrolyte Membranes
Hybrid Rotaxanes: Interlocked Structures for Quantum Computing?
P-Glycoprotein Structure and Chemotherapy Resistance
Molecular-Frame Angular Distributions of Resonant Auger Electrons
Self-Assembly of Polymer Nano-Elements on Sapphire
Enzyme Structure Provides Insights into Cancer and Aging