Upper bound correlation, polymer

Figure 11.1 Polymer upper bound correlation for C02/CHj separation [3, 4].

An opposite, strong-coupling limit has also been used to describe excitons in conjugated polymers (Gallagher and Mazumdar 1997 Gebhard et al. 1997 Essler et al. 2001 Harford 2002). As described in the previous chapter, in this limit a correlation gap separates the electron removal spectral weight (the lower Hubbard band) from the electron addition spectral weight (the upper Hubbard band). Now the bound particle-hole excitations are Mott-Huhhard excitons. That is, a particle excited from the lower Hubbard band to the upper Hubbard band... 

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