Enhanced X-Ray Imaging Determines Molecular Structure

For more than 100 years, X-rays have been used in crystallography to determine the structure of molecules. At the heart of the method are the principles of diffraction and superposition, to which all waves are subject. Light waves consisting of photons are deflected by the atoms in the crystal and overlap — like water waves generated by obstacles in a slowly flowing stream. If a sufficient number of these photons can be measured with a detector, a characteristic diffraction pattern or wave pattern is obtained from which the atomic structure of the crystal can be derived. This requires that photons are scattered coherently, meaning that there is a clear phase relationship between incident and reflected photons. This corresponds to water waves that are deflected from the obstacles without vortexes or turbulences. If photon scattering is incoherent, the fixed phase relationship between the scattered photons disperses, making it impossible to determine the arrangement of the atoms — just like in turbulent waters.