X-ray diffraction
(Also known as crystallography)
Crystals are made up of atoms arranged in a lattice. X-ray photons aimed at a crystal interact with the lattice atoms and the photons ‘bounce off’ the atoms’ electrons. This ‘bounce-off ‘ occurs at an angle which changes according to the arrangement of the lattice atoms, and this lattice arrangement differs according to the material from which the crystal is made.
X-rays which have bounced off (been diffracted by) the crystal atomic lattice will expose a sheet of photographic paper placed behind the crystal. When the paper is developed the resulting photograph shows the pattern produced by the diffracted X-rays.. This pattern is unique to the lattice structure and identifies the material from which the crystal is made. The technique is used to identify the molecular structure of materials.
X-ray diffraction was first discovered by Von Laue* , developed by Bragg* and was used in the identification of DNA by Crick & Watson in 1953*. “...X-ray crystallography of biological molecules took off with Dorothy Crowfoot Hodgkin, who solved the structures of cholesterol (1937), penicillin (1946) and vitamin B~12 (1956), for which she was awarded the Nobel Prize in Chemistry in 1964. In 1969, she succeeded in solving the structure of insulin, on which she worked for over thirty years....
ONELINER: X-ray diffraction
OTHER CONNECTIONS: None
BIBLIOGRAPHY:
EB