Observation of dynamic extinction due to a glide plane perpendicular to an incident beam by convergent-beam electron diffraction

The rules for dynamic extinction in electron diffraction, occurring in kinematically forbidden reflections due to screw axes or glide planes, were given by Gjønnes and Moodie [Acta Cryst. 19 (1965) 65]. Among the rules, the dynamic extinction due to a glide plane which is set perpendicular to the incident beam has not yet been observed. The observation of this extinction using convergent-beam electron diffraction is reported here for the 420 reflection of spinel and the 200 reflection of silicon. On the basis of experimental results, a practical rule is given for this extinction.