Electron microscopy and diffraction of solid α-N₂

Using a pressure cell in conjunction with a liquid helium stage, single crystals of α-N2 have been produced and studied in an electron microscope. Single crystal diffraction patterns of α-N2 have been observed for the first time, and are correlated with the proposed structure. Twins, dislocations and faults have been observed and a start has been made towards understanding their nature. Electron microscope contrast parameters have been calculated for this structure, including approximately the effects of molecular rotation and electronic excitation.