A common situation found in condensed phases under illumination is for all levels, except electronic levels, to be thermally equilibrated. Thus, under constant illumination, the sample is a mixture of thermally/vibrationally-equilibrated ground-state(s) with a very small, non-Boltzmann population of the excited electronic state, but which is itself thermally and vibrationally Boltzmann distributed. So the situation is similar to two non-equilibrated chemical species each of which is thermally equilibrated a thermally equilibrated ground-state, and a thermally equilibrated high energy excited-state. [Pg.68]

Implicit solvation models developed for condensed phases represent the solvent by a continuous electric field, and are based on the Poisson equation, which is valid when a surrounding dielectric medium responds linearly to the charge distribution of the solute. The Poisson equation is actually a special case of the Poisson-Boltzmann (PB) equation PB electrostatics applies when electrolytes are present in solution while the Poisson equation applies when no ions are present. Solving the Poisson equation for an arbitrary equation requires numerical methods, and many researchers have developed an alternative way to approximate the Poisson equation that can be solved analytically, known as the [Pg.125]

© 2019 chempedia.info