Molecule azobenzene molecular layers

The crystal structure can be considered as a structure regularly stacked with bimolecular layers along the a-axis. Within the bimolecular layer, two molecules related by inversion symmetry face each other in the tail-to-tail fashion with their molecular axes inclined by about 26° to the bilayer surface. This inclination enables the head-to-tail arrangement of azobenzene chromophores as expected from the spectroscopic study. 

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