Transmission electron diffraction

Takayanagi K, Tanishiro Y, Takahashi M and Takahashi S 1985 Structural analysis of Si(111)-7 7 by UFIV-transmission electron diffraction and microscopy J. Vac. Sot Technol. A 3 1502... 

One fiirther method for obtaining surface sensitivity in diffraction relies on the presence of two-dimensional superlattices on the surface. As we shall see fiirtlrer below, these correspond to periodicities that are different from those present in the bulk material. As a result, additional diffracted beams occur (often called fractional-order beams), which are uniquely created by and therefore sensitive to this kind of surface structure. XRD, in particular, makes frequent use of this property [4]. Transmission electron diffraction (TED) also has used this property, in conjunction with ultrathin samples to minimize bulk contributions [9]. 

Takayanagi K 1990 Surface structure analysis by transmission electron diffraction—effects of the phases of structure factors Acta. Crystalloger A 46 83-6... 

Speer, S., Spence, J.C.H. and Ihrig, E. (1990) On differentiation of the scattering matrix in dynamical transmission electron diffraction, Acta Cryst. A, 46, 763-772. 

Interaction of incident electrons with the electrostatic potential (ESP) gives the possibility to reconstmct the potential from transmission electron diffraction (ED) experiments. ESP and the electron density determine all physical properties of crystals (e.g. energy of electrostatic interaction, characteristics of the electrostatic field in crystals, dipole, quadmple and other momentum of nuclear, diamagnetic susceptibility. 

The ideal layered silicate is the mineral montmorrillonite, which is main component of the clay bentonite (fig 6). Montmorrillonite is a so called 2 1 layered silicate. Each layer consists of two sheets of silica tetrahedrae which are sandwiched by an alumina octahedrae sheet. The layers are only weakly bound, often by hydrogen bonding from water. The structure has been extensively studied by transmission electron diffraction especially by Z5wagin and coworkers [4]. 

Table 5.1. Adsorption properties of metal monolayers on metal substrates. The clean substrate properties are also given for comparison. Substrates are ordered by lattice type (fee, bcc, hep, cubic, diamond and rhombic). The structures, nearest neighbor distances and heats of vaporization refer to the bulk material of the substrate or the adsorbate. VD, ID and S stand for vapor deposition, ion beam deposition and surface segregation, respectively. TD, WF and TED stand for thermal desorption, work function measurements and transmission electron diffraction, respectively...

Takayanagi, K. et al. Structure Analysis of the Silicon(lll) 7x7 Reconstructed Surface by Transmission Electron Diffraction/5 Surface Science, 164, 367 (1985). Tromp, R.M. and E.J. van Loenen Ion-Beam Crystallography on Silicon Surfaces III. Si(lll),5 Surface Science, 155, 441 (1985)... 

Recent relevant work has made use of transmission electron diffraction, the theory of which we discussed in Section 2.5. This technique has a very straightforward interpretation which, combined with improved experimental methods, has provided very precise results. Two papers are of particular importance in this context. Garoff et al. [137] studied monolayers of cadmium stearate. Their substrates were 2 nm layers of SiO coated on 10 nm layers of amorphous carbon on 200 mesh Ni elec-... 

Fig. 4.6. XRD of PQT-12 (a) pressed pellet of precipitated polymer from polymerization (b) pressed pellet annealed at 140 °C (c) as-cast 0.2-pm thin film (d) 0.2-pm thin film annealed at 135 °C and (e) transmission electron diffraction pattern of PQT-12 film on carbon grid [36],...

Takayanagi K, Tanishiro Y, Takahashi S, Takahashi M (1985) Structure analysis of silicon(l 11)-7x7 reconstructed surface by transmission electron diffraction, Surf. Sci. 164 367-392... 

Figure 4.4 has been drawn for the Laue case, in which the diffracted waves are directed into the crystal. This is the appropriate case for transmission electron diffraction in which n is usually nearly normal to g. 

In a transmission electron diffraction experiment (which is essentially a symmetrical Laue case), the electron flow (current) is on the average parallel to the atomic (reflecting) planes. However, it can be seen from the expressions for and which have just been derived that the prob-... 

Structure analysis. The particles were suspended in alcohol and put on a carbon substrate. They were examined in a Philips 301 electron microscope. Bright field, dark field and interference image micrographs on a high resolution stage were taken as well as transmission electron diffraction patterns. The lattice parameter of powders was determined by X-ray diffraction using Cu Ka radiation. 

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