EARN atom distributions

The EARN distributions of Rh atoms ejected from 0/Rh(l 11H2 x 2) have recently been measured. In addition simulations were performed for the oxygen atoms in both of the three-fold sites and for both the 0.25 and 0.5 monolayer coverages. Experimentally the Rh atom yield decreases by about a factor of two with the oxygen adsorption. To reproduce this effect in the simulations the 0.5 monolayer coverage was required. In the experimental... 

EARN distributions the yield along the azimuth 4>= —30° was preferentially reduced with respect to = + 30°. In agreement with intuition, the calculations confirm that the oxygen atom resides in the C-site. Thus from the cooperation of EARN experiments and computer simulations the coverage and nature of the adsorption site of 0/Rh(l 11) has been determined. It will be of interest to see if other surface structure techniques can be used to confirm these s Kcific surface structures. 

The importance of radical polymerizations can be ascribed to the large variety of vinyl monomers that can be polymerized and copol erized and to the undemanding experimental conditions (7). Radical polymerizations require the absence of oxygen but can be earned out in the presence of water and other impurities. In addition, radical polymerizations are tolerant to many functional groups. Mth atom transfer radical polymerization (ATRP), it is now possible to conduct radical polymerizations in a controUed/ living fashion (2-4). Structural variables of polymeric chains such as molecular wei t, molecular weight distribution (4), copolymer composition (5-ri) and terminal functionalities can be controlled (7). Furthermore, a variety of molecular architectures can be prepared such as linear, branched and hyperbranched structures (8). 

This model was not correct, of course. First of all, almost all atoms also contain neutrons (the only exception being the lightest isotope of hydrogen, H-1), but the neutron was not discovered until 1932, so it did not play a role in models of the atom during the first three decades of the twentieth century. Secondly, the protons and electrons in atoms are not uniformly distributed, but another experiment had to be done to figure that out. Thomson s discovery of the electron, however, earned him the 1906 Nobel Prize in physics. 

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