Before you read this, I suggest you read post 22.12 and appendix 3 of post 22.20. When you read the title, this may seem like a very obscure topic. But it isn’t because we need to understand the Fourier transform of a lattice to understand x-ray diffraction by a crystal. And we need to understand… Continue reading 22.22 Fourier transform of a one-dimensional lattice

In post 16.37 we saw that the atoms or molecules or ions in a solid are packed together so that the solid is completely contained within its free surfaces – it forms an object that we can hold without it flowing through our fingers. In an ideal gas, the atoms or molecules are free to… Continue reading 22.21 An ideal crystal