Intensity Anomaly in Kikuchi Lines of Molybdenite.

Abstract

Kikuchi patterns of normal and anomalous molybdenites [Uyeda: Acta Cryst. A24 (1968) 175] were taken with a high voltage electron microscope at 350 kV and 500 kV. Many of the Kikuchi lines were indexed systematically. The normal molybdenite is polytype 2H₁, as is known, and the anomalous one is likely to be 2H₂ or 2T. The anomalous extinction of 400 and 700, as pointed out by Uyeda, was observed for the normal molybdenite, while their structure factors do not vanish. It is concluded that this effect is not due to another polytype, but to a dynamical many-beam interaction.