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Au Two-Atom Interaction
Single atoms of gold are easily observed on the surface of the carbon film. These move around, partly in response to interactions with other atoms, partly by thermal fluctuations, and partly by interaction with the electron beam. When two of them approach, they feel an attractive force. As they approach closer, this attractive force turns into a repulsive force. This can be seen in real time: sumamrized by the frames labeled by time. In this case, two atoms approach, circling one another (indicated by the arrows). Then one of the atoms moves rapidly away to a spot about 0.5 nanometers distance away. Finally the other atom follows. These frames are taken from the AVI Animation 1.
Real time movie that shows the two atom interaction
(AVI Animation 1, .3 MB)
This sequence shows the dissolution of a gold crystal under influence of the electron beam. The crystal changes its shape, and atoms evaporate away from it. At one point the whole atom cluster explodes into individual atoms, and the reforms into a smaller cluster. It does this at least one more time becore is has completely disassembled into single atoms which disperse.
(AVI Animation 2, 7.2 MB)
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