Premium
Prospects for the direct electron crystallographic determination of zeolite structures
Author(s) -
Dorset Douglas L.,
McCourt Mary P.
Publication year - 1997
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/(sici)1097-0029(19970201)36:3<212::aid-jemt9>3.0.co;2-q
Subject(s) - electron crystallography , electron diffraction , resolution (logic) , crystal (programming language) , diffraction , electron , scattering , fourier transform , electron scattering , reflection high energy electron diffraction , gas electron diffraction , electron microscope , chemistry , molecular physics , crystallography , optics , physics , quantum mechanics , artificial intelligence , computer science , programming language
Recently two successful zeolite structures based on experimental electron crystallographic data have been published. Diffraction and image data based on the silicate portion of the zeolite, mordenite, which are perturbed by dynamical (as well as secondary) scattering, have been simulated by a multiple‐beam dynamical scattering program. Structure analyses with these data show that the above claims are not unreasonable, given a high enough accelerating voltage for the electron beam. If, for example, 2.9 Å resolution micrographs are taken from a 120 Å thick crystal in a 200 or 400 kV electron microscope, the crystallographic phases found by image analysis (Fourier filtration) are accurate enough to be extended by the Sayre equation to the (atomic) resolution limit of the electron diffraction pattern (for example from a 105 Å thick crystal illuminated by a 1,200 kV electron source). The resultant potential map can be interpreted to find most of the atomic positions and the remaining ones will appear during the progress of a Fourier refinement. Microsc. Res. Tech. 36:212–223, 1997. © 1997 Wiley‐Liss, Inc.