Stochastic model for photoinduced anisotropy

We present a stochastic model for the kinetics of photoinduced anisotropy in a sample of molecular chromophores that may undergo photoisomerization. It is assumed that the chromophores do not interact among them, but are embedded in a medium that slows down the rotational diffusion. The model makes use of data about the photoinduced reorientation of the single chromophore, its photoisomerization and its rotational diffusion, that are made available by molecular dynamics simulations. For the first time such molecular scale processes are computationally connected to the development of anisotropy in a large sample and on a long time scale. A test on azobenzene shows the potentiality of the method and the interplay between photoinduced anisotropy and photoisomerization.