NEW METHOD OF BRAVAIS LATTICE DETERMINATION

A new method of Bravais lattice determination from a single convergent beam electron diffraction (CBED) pattern is proposed. The method is b ased on the principle that a primitive reciprocal lattice cell can be measured accurately from the deficiency line of medium or high order r eflections or high order Laue zone (HOLZ) line positions within the ce ntral disk of a single CBED pattern taken near an arbitrary zone axis. This primitive cell can be reduced to the unique Niggli cell and thus the Bravais cell by Krivy and Gruber reduction procedures. This metho d could be very useful in identifying phase of mixed phase materials o r as the first step toward determination of a new structure or as an a utomated procedure of indexing diffraction patterns of known structure .