Interaction space, molecular

The physical condition of the kinetic theory of gases can be described by elastic collisions of monodispersed spheres with the Maxwellian velocity distribution in an infinite vacuum space. Therefore, for an analogy between particle-particle interactions and molecular interactions to be directly applicable, the following phenomena in gas-solid flows should not be regarded as significant in comparison to particle-particle interactions the gas-particle... 

Proteochemometrics A Tool for Modeling the Molecular Interaction Space... 

Recall that in the MO model for the gaseous Li2 molecule (Section 9.3), two widely spaced molecular orbital energy levels (bonding and antibonding) result when two identical atomic orbitals interact. Flowever, when many metal atoms interact, as in a metal crystal, the large number of resulting molecular orbitals become more closely spaced and finally form a virtual continuum of levels, called bands, as shown in Fig. 10.19. 

In the case of samples that produce scatter in transmission or diffuse reflectance spectra, a number of factors corrupt the linearity of the Beer-Lambert absorbance concentration relationship. Sample scattering of radiation results in an alteration of the proportion of absorbed and reflected radiation so that pathlength becomes another unknown in the Beer-Lambert relationship. Particle size, particle shape, crystalline form, bulk, density, and the nature of the pore space (filled with air, water, or oil) are all variables that dictate the effective pathlength of the radiation. Sample surfaces also reflect specular energy that has not interacted with molecular structures. This form of energy has an overall effect on spectra, contributing primarily to the curvilinearity of the spectral baseline. 

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