Model photoisomerization as a sequence of thermal operations
“Isomers are molecules with the same number of atoms of each element but distinct arrangements of atoms in space.”
Photoisomerization is isomerization induced by photoexcitation.
“Photoisomerization of the compound retinal in the eye allows for vision.”
Let φ be “the relative rotation of two molecular components around a double bond”.
“Photoisomerization as a sequence of three Thermal operations: photoexcitation, rotation and thermalization.”
Molecule starts in thermal equilibrium with its environment at an inverse temperature β.
Photoexcitation A light source excites the electronic state of the molecule at the fixed angular coordinate φ = 0; The molecule ends up in a new electronic state ρi.
Rotation Two molecular components can then rotate relative to each other while relaxing in contact with the environment; The molecule ends up in a state ρf which will have some weight on the cis configuration φ = π.
Thermalization The molecule thermalizes again.