Electron transport partially localized

An X-ray photoelectron spectroscopic study of Ni(DPG)2I showed no evidence of trapped valence or any appreciable change in the charge on the metal upon oxidation.97 The site of partial oxidation and hence the electron transport mechanism is still unclear but one explanation of the relatively low conductivity is that the conduction pathway is metal centred and that the M—M distances are too long for effective orbital overlap. Electron transport could be via a phonon-assisted hopping mechanism or, in the Epstein—Conwell description, involve weakly localized electronic states, a band gap (2A) and an activated carrier concentration.101... 

It was pointed out in Chapter I that the / electrons are always best described by a HL approach, but that the d electrons may be described by either a collective or a localized model, depending upon the situation. If a collective description is appropriate for some of the d orbitals and the corresponding d states are only partially occupied, the compound is metallic (or has a small activation energy for electron transport if R Rc and there is an integral number of d electrons per atom) unless the cations themselves form a two-... 

In Section 3.11.2 we discussed the phenomenological model of electron transport in the conduction band of tetramethylsilane modulated by trapping by biphenyl. Such a model can be generalized for the electron transport in low mobility hydrocarbons, as, for instance, n-hexane. Localized electrons have been detected by their optical absorption. The traps in hydrocarbons are assumed to be structural voids which upon occupation by an electron increase further in depth. The electrons are only partially localized in these traps (Schiller et al., 1973). By thermal activation they... 

From these time-scales, it may be assumed in most circumstances that the free electrons have a Maxwellian distribution and that the dominant populations of impurities in the plasma are those of the ground and metastable states of the various ions. The dominant populations evolve on time-scales of the order of plasma diffusion time-scales and so should be modeled dynamically, that is in the particle number continuity equations, along with the momentum and energy equations of plasma transport theory. The excited populations of impurities on the other hand may be assumed relaxed with respect to the instantaneous dominant populations, that is they are in a quasi-equilibrium. The quasi-equilibrium is determined by local conditions of electron temperature and electron density. So, the atomic modeling may be partially de-coupled from the impurity transport problem into local calculations which provide quasi-equilibrium excited ion populations and effective emission coefficients (PEC coefficients) and then effective source coefficients (GCR coefficients) for dominant populations which must be entered into the transport equations. The solution of the transport equations establishes the spatial and temporal behaviour of the dominant populations which may then be re-associated with the local emissivity calculations, for matching to and analysis of observations. 

That is, the concentration of cation vacancies is proportional to the eighth root of the partial pressure of oxygen in the case of the above mentioned ideal conditions. Now, in CU2O the transport number of the electronic charge carriers is one, and the diffusion of copper ions via vacancies is rate-determining. Thus, if local defect equilibrium is assumed, it follows from eq. (8-14) that the component diffusion coefficient varies as p l according to the equation ... 

Conducting polymers are partially crystalline and partially amorphous hence, they consist of both delocalized and localized states. The delocalization of ir electrons depends on the extent of disorder, interchain interactions, etc. The disorder-induced localization plays a dominant role in the metal-insulator (M-I) transition and transport properties of conducting polymers. Moreover,... 

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