Energy effect, intrachain

Band Structure Calculations and Experimental Results The spectroscopic properties discussed above are related primarily to intrachain electronic structure. One exception is the stability of gap states (e.g., polarons) versus the three-dimensional interaction effects mentioned in Chapter 11, Section IV.D. Energy and charge transport are, of course, dependent on interchain transfers. So while there are only a few three-dimensional band structure calculations (e.g., for PA [184] and PPV [185]), there are many theoretical calculations concerning infinite perfectly periodic one-dimensinal chains, the effects of local perturbations, and the elementary excitations of these chains solitons, polarons, and bipolarons. Only a few hints of that work will be given here. It has been discussed and reviewed several times (see, e.g., Refs. 186 to 188). 

Yersin and colleagues have investigated the effect of pressure on the polarized emission properties of a number of Pt (CN) chain systems over the past several years [215,216,219-223]. The objective of their studies is to use pressure to examine the effect of intrachain Pt-Pt distance on the energy and intensity of exciton emission. In contrast to the effect of variations in the chemical identity of charge balancing cations, high pressure provides a method to continuously decrease the intrachain Pt-Pt distance. 

As described in Chapter 6, n = 1 corresponds to the Sx and T% families of intrachain excitons, while n = 2 corresponds to the ct and Tct families of intrachain excitons. The lowest energy branch of each family has the smallest pseudo-momentum, namely, j =. The effective-particle model is illustrated in Fig. 6.2. 

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