Atoms viewing with microscope

Electrons residing in molecular clusters can be viewed as microscopic probes of both the local liquid structure and the molecular dynamics of liquids, and as such their transitory existence becomes a theoretical and experimental metaphor for one of the major fundamental and contemporary problems in chemical and molecular physics, that is, how to describe the transition between the microscopic and macroscopic realms of physical laws in the condensed phase. Since this chapter was completed in the Spring of 1979, several new and important observations have been made on the dynamics and structure of e, which, as a fundamental particle interacting with atoms and molecules in a fundamental way, serves to assist that transformation for electronic states in disordered systems. In a sense, disorder has become order on the subpicosecond time-scale, as we study events whose time duration is shorter than, or comparable to, the period during which the atoms or molecules retain some memory of the initial quantum state, or of the velocity or phase space correlations of the microscopic system. This approach anticipated the new wave of theoretical and experimental interest in developing microscopic theories of... 

With standard graphics, a beginning student can literally view the microscopic structure of a liquid as produced with a molecular dynamics or Monte Carlo computer- simulation. The relative arrangements of atoms are disordered, fluctuating and, therefore, responding to disturbances or probes of liquid structure. Despite its chaotic nature, however, there are many important regularities, and these are best described with the principles of statistical mechanics and correlation functions. 

The Orbital Model As an Approximation. The quantum mechanical revolution also implies a more technical modification to our view of microscopic phenomena. Whereas the old quantum theory, as perfected by Pauli, required the assignment of as many as four quantum numbers to each electron in a many-electron atom, the arrival of quantum mechanics showed that even this more abstract notion is strictly inconsistent in any atom other than hydrogen. This result can be expressed by saying that individual electrons in a many-electron atom are not of themselves in stationary states whereas the atom as a whole does possess stationary states. This change in perspective is far from trivial and shows definitively that the orbital model is an approximation in many-electron systems. It also requires that the scientific term orbital is strictly non-referring with the exception of when it applies to the hydrogen atom or other one-electron systems. ... 

Figure 1.1 (a) Real heterogeneity of a catalyst from the centimetric level to the nanoscale (atomic) level (b) a cubo-octahedral model of a metal particle and an electron microscope view of a platinum particle covered with n-octylsilyl fragments). (Unpublished results with permission of the Fritz Haber Institute, Berlin.)... 

With the development of quantum mechanics at the beginning of the 20th century it became clear that microscopic particles such as atoms, electrons and neutrons, in some cases behave like waves. Both views, the classical picture of a particle characterized by a momentum p, and that of a wave with a wavelength A, are only two different, complementary, viewpoints of the same physical object. Both quantities are related by the de Broglie2 relation A = h/p, where... 

Macrosculptures, three-dimensional works of art, are found just about anywhere people congregate. They make our world a pleasant and interesting place. Not all sculptures are made by artists Plants and geologic formations provide us with natural three-dimensional macroscopic sculptures. Atoms and molecules are viewed at the microscopic level. We have been referring to these sculptures as microsculptures because... 

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