Classical Mechanics Models

The differences just outlined cannot be explained by means of a classical mechanical model. However, they can be explained by considering chemical bonding. In particular, hardness depends in covalent crystals on the fact that the valence (bonding) electrons are highly localized as shown by electron-diffraction studies which can provide maps of electron densities (bonds). 

One difficulty with the Slater and RRK theories as we have employed them lies in the use of a classical mechanical model of a molecule. The first formulation of the problem of a chemical reaction in quantum-mechanical terms was made by London, who used a very crude approximation to resolve the problem mathematically. A study by Golden et al. ... 

The usual image of a molecule invoked in contemporary chemistry is a curious combination of quantum mechanical and classical mechanical models. Whereas it is well accepted that even a crude description of the electron distribution within a molecule must rely on quantum mechanics leading, for example, to various... 

The refined model is also a classical mechanical model of the reactive collision event, in which both the long-range polarization and short-range repulsive forces are taken into account. In doing so, the model assumes that the repulsive forces are impulsive at the reaction radius , and for this reason the model is referred to as the impulsive model . 

With these possibilities in mind, we plot the courses in temperature of the fluid- and solid-phase entropies for hard- and soft-sphere systems, and compare them with the MD results in Figs. 21 and 22. It should be noted that in classical mechanical models the entropy is usually defined relative... 

The classical mechanical model of unimolecular decomposition developed by Slater (1959) is based on the normal mode harmonic oscillator Hamiltonian, Eq. (2.47). 

Figure A9.4a illustrates the classical mechanics model of an electron circling a fixed, positively charged nucleus. The electron moving on an orbit around the nucleus has a velocity which continually changes direction but not magnitude. A changing velocity...

Vibrations in the molecule are small oscillations of the atoms around their equilibrium positions. In a classical mechanical model, the vibrations in the molecules can be described by the harmonic oscillator. According to this, frequency of a... 

A convenient classical mechanical model of a diatomic molecule includes the following types of motion, assumed, at a first approximation, as independent ... 

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