What is the Patterson calculation?

The Patterson calculation, often referred to in the context of crystallography, is a method used to derive electron density maps from X-ray diffraction data. It involves creating a Patterson function, which is a mathematical representation of the Fourier transform of the crystal's structure factors, capturing the distribution of interatomic vectors. This technique helps identify the positions of atoms within a crystal structure by analyzing the peaks in the Patterson map, providing a starting point for more detailed structural analysis.