Gold crystals, diffraction

P. Chen, I. V. Tomov, and P. M. Rentzepis, Time resolved heat propagation in a gold crystal by means of picosecond X-ray diffraction. J. Chem. Phys., 104(24), 10001-10007 (1996). 

Fig. 4 Transmission electron micrographs of a highly facetted mostly triangular gold particles, b a hexagonal particle, c electron diffraction pattern of the triangular particle showing that it is a single crystal. Diffraction from the (111), (220), (311), (331), (422) planes are identified...

A quantitative measurement of the depth of penetration of the diffracted electrons has been made previously by the author (1) by depositing silver vapor onto a gold crystal surface, using a calibrated silver source. Since the lattice structures are the same and the lattice constants differ by less than 0.4%, the silver was found to deposit as a thin crystal on the gold surface. Because of the different indices of refraction and certain fine-structure characteristics for the two metals, the diffraction beams from silver and gold were readily distinguished. 

The second-order diffraction ( = 2) for a gold crystal Is at an angle of 22.20° for X rays of 154 pm. What is the spacing between these crystal planes ... 

FIGURE 1.21 Davisson and Germer showed that electrons produce a diffraction pattern when reflected from a crystal G. P. Thomson, working in Aberdeen, Scotland, showed that they also produce a diffraction pattern when they pass through a very thin gold foil. The latter is shown here. G. P. Thomson was the son of J. J. Thomson, who identified the electron (Section B). Both received Nobel prizes 1.1. for showing that the electron is a particle and G. P. for showing that it is a wave. 

Figure 8. Image and diffraction pattern from an (100) epitaxial. specimen of gold prepared in an unbaked UHV evaporator by depo.sition onto KOI and then transfer onto amorphous carbon. Here water vapour was the dominant residual gas (determined by mass spectrometry). The particles are square pyramidal single crystals.

The reaction of the trimethyl tritiophosphite and triphenyl tritiophosphite with the gold derivative [Au(C6F5)(tht)] leads to the gold(I) complexes [57] shown in Figure 3.6. The crystal structure of the trimethyl tritiophosphite gold (I) complex was studied by X-ray diffraction and two different polymorphs were discovered. 

Figure 8.26 Schematic formula (a) molecular single crystal X-ray diffraction structure (b), and solid state packing (c) ofthe cationic gold complex [Au bimy(Ci6H33) 2]Br H20. (Reproduced from Ref [52] by permission.)...

FIG. 20-24 High -resolution TEM image of Si nanowires produced at 500 C and 24.1 MPa in supercritical hexane from gold seed crystals. Inset Electron diffraction pattern indexed for the <111> zone axis of Si indicates <110> growth direction. [Reprinted with permission from Lu et al. Nano Lett., 3(1), 93-99 (2003). Copyright 2003 American Chemical Society. ]... 

Strong L, Whitesides GM (1988) Structures of self-assembled monolayer films of organosulfur compounds adsorbed on gold single crystals electron diffraction studies. Langmuir 4 546-558... 

In the present paper non-conventional TEM methods to characterize small metallic particles are presented. The topographic information on the particles shape can be combined with micro-diffraction (using STEM) data to obtain a full characterization of the particle. The case of gold particles evaporated on a NaCl substrate is used as example. The particle shapes observed are discussed. It is shown that many particles have a crystal structure which is different from the bulk (Fee). 

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