Thompson atomic model

Thompson developed an atomic model, the raisin pudding model, which described the atom as being a diffuse positively charged sphere with electrons scattered throughout. 

Know what part Dalton, Thompson, Millikan, and Rutherford had in the development of the atomic model. 

Rutherford was surprised when some of the a-particles bounced back. He was surprised because he was thinking of Thompson s model of the atom. What if Rutherford believed atoms were as Dalton envisioned them What do you suppose Rutherford would have expected, and what would have surprised him ... 

In a recent review, Haruta has reassessed the mechanism of CO oxidation on the basis of the Bond and Thompson and Kung models, i.e. that the CO is activated by adsorption on Au° on the surface of the gold nanoparticles and that dioxygen is activated by the atoms at the periphery between the support and the gold nanocrystals (Fig. 4.7). The atoms at the periphery are proposed by Haruta to be cationic in nature, possibly Au(OH)s or Au(OH) formed by the presence of water vapor that is essential for the observed high activity catalysts. It is clear that the debate will continue for the immediate future. There are two reasons why finding an answer to the key question of the nature of the active site in gold catalysts for CO oxidation. The first is purely scientific... 

In an effort to understand silicon surface diffusion, NoorBatcha, Raff and Thompson have employed molecular dynamics to model the motion of single silicon atoms on the Si(001) and Si(lll)surfaces. Morse functions are used for the pair forces, with the parameters being determined by the heat of sublimation. Because different forces were used for the diffusing and substrate atoms, the incorporation of gas-phase species into the crystal could not be directly modeled. Nonetheless, they were able to explore the characteristics of adsorption and diffusion for single atoms. 

In a subsequent study, Agrawal, Raff and Thompson showed that the sticking probability for the molecule was independent of the interactions used for the substrate atoms. The mobility of the H atoms and the rate of energy transfer between the H atoms and the substrate, however, were reported to depend somewhat on the lattice. Despite the small dependence on the substrate model, the major results of the initial study remained unchanged. 

Breneman, C. M., Thompson, T. R., Rhem, M., and Dung, M. (1995) Electron density modeling of large systems using the transferable atom equivalent method. Comp. Chem. 19, 161-179. 

Bond valences can be used in conjunction with other techniques, particularly powder diffraction where, for example, light atoms are difficult to refine in the presence of heavy atoms. Adding the chemical constraints of the bond valence model can stabilize the refinement, particularly in the case of superstructures that have high pseudo-symmetry (Thompson et al. 1999). 

An overview of a scientific subject must include at least two parts retrospect (history) and the present status. The present status (in a condensed form) is presented in Chapters 2-18 of this book. In this section of the overview we outline (sketch) from our subjective point of view the history of electrochemical deposition science. In Section 1.2 of this chapter we have shown the relationship of electrochemical deposition to the rest of the sciences. In this section we show how the development of electrodeposition science was dependent on the development of physical sciences, physics and chemistry, in general. It is interesting to note that the electron was discovered in 1897 by J. J. Thompson and the Rutherford-Bohr model of the atom was formulated 1911. 

The values of the parameter y corresponding to experimental dependences of zeff on the charge Z, have been found in Ref. 178. Using the statistical Fermi-Thompson model of an atom, the authors have calculated the velocity distribution of external electrons for atoms of heavy elements. Using the Bohr criterion, they have obtained a formula for zeff of the form (5.7) with the exponent of Z, equal to For this value of y the calculated values of zeff for heavy fission fragments in a hydrogen medium practically coincide with the experimental ones. 

Figure 1. The diatom Aulonia hexagona is an almost perfect 100000-fold model of a giant fullerene with about 1200 carbon atoms. (From On growth and form, by W. D Arey Thompson. Courtesy of Cambridge University Press.)...

In the development of the set of intermolecular potentials for the nitramine crystals Sorescu, Rice, and Thompson [112-115] have considered as the starting point the general principles of atom-atom potentials, proven to be successful in modeling a large number of organic crystals [120,123]. Particularly, it was assumed that intermolecular interactions can be separated into dispersive-repulsive interactions of van der Waals and electrostatic interactions. An additional simplification has been made by assuming that the intermolecular interactions depend only on the interatomic distances and that the same type of van der Waals potential parameters can be used for the same type of atoms, independent of their valence state. The non-electric interactions between molecules have been represented by Buckingham exp-6 functions,... 

AtomStru Structure of the Atom - Dalton, Thompson and Rutherford Models - Atomic Number - Atomic Weights - Isotopes. 

Thompson et al. (302) have also made a number of pair-of-noninter-acting-dimers structures. In [Cu2L (p,3-0H)(N03)3(H20)]2, the four Cu atoms are linked by both diazine and pyramidal p-s-OH bridges, thus forming a central Cu2(m3-OH)2 ring with Cu-- Cu separations similar to those in the moieties. A one-J dimer model was adequate to... 

Science often develops by using the known theories and expanding, refining, and perhaps changing these theories. As discussed in Section 4.5, Rutherford used Thompson s ideas when thinking about his model of the atom. What if Rutherford had not known about Thompson s work How might Rutherford s model of the atom have been different ... 

As indicated above. Figure 4.32 shows that maximum removal of n-hexade-eane, which is widely used as a model compound representing mineral oils, occurred near the PIT. Similar results were found for 50/50 mixtures by weight of n-hexadecane and squalane, a highly branched hydrocarbon containing 30 carbon atoms (Raney et al., 1987). Thompson (1994) found similar behavior with n-decane. However, maximum removal of pure squalane with solntions of CjjEj occurred at approximately 40°C, well below the PIT of 63°C. Based on contact angle measurements, Thompson attributed this behavior to the fabric being rather oil wet at the PIT of squalane, which made the oil more difficnlt to remove. 

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