Chiral vibronic transitions

Circular Dichroic Intensities in the Vibronic Transitions of Chiral Metal Complexes... 

Then, there are model Hamiltonians. Effectively a model Hamiltonian includes only some effects, in order to focus on those effects. It is generally simpler than the true full Coulomb Hamiltonian, but is made that way to focus on a particular aspect, be it magnetization, Coulomb interaction, diffusion, phase transitions, etc. A good example is the set of model Hamiltonians used to describe the IETS experiment and (more generally) vibronic and vibrational effects in transport junctions. Special models are also used to deal with chirality in molecular transport junctions [42, 43], as well as optical excitation, Raman excitation [44], spin dynamics, and other aspects that go well beyond the simple transport phenomena associated with these systems. 

As temperature decreases, the aggregation of the polymers increases. This change in the conformational structure is manifested in a permutation of the absorption spectrum, hence thermochromism [1,11,26,27,92,122-124,180-182]. Thermochromism was clearly shown for poly(3-(2-methyl-l-butoxy)-4-methylthiophene) (PMBMT). A thin film of PMBMT, in the presence of acetone vapor, shows a A ax of 502 nm with vibronic sidebands at 534 and 582 nm. Upon heating above the Tg (50°C), the spectrum blueshifts dramatically afford to a A ax of372 nm. This process was irreversible [ 183]. Thermochromism has also been shown in PATs with chiral substituents. Thin films of poly[3-(S)-2-methylbutylthiophene] show a redshift after heating, indicating a conformational transition that provides a structure with more efficient orbital overlap [90]. 

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