Electron Microscope Investigation of Crystals Based on Bend-Contour Arrangement. I. Relationship between Bend-Contour Arrangement and Bend Geometry

The relationship between bend—contour patterns in electron micrographs and sample crystallography, buckling, and orientation is examined in the case of cylindrical bending. The principles, determining the structure of extinction contour patterns (sequence, spacing), with the bend axis deflected from the perpendicular direction to the electron beam and the reciprocal lattice plane (which provides the observed reflections) deflected from the film plane, are set forth. Relationships between the bending radius and the contour spacing, from which earlier known formulae may be derived as a particular case, are established. The established principles are demonstrated on thinfilm hexagonal selenium crystals and may serve as a basis for the study of more complex cases of bending.