Demos.MolElectronic.Retinal
WavePacket demo example: Isomerization of retinal molecule
The photoinduced isomerization of the retinal molecule in rhodopsin is considered as the primary step in vision. Here it serves as a real-life example for the importance of avoided crossings and conical intersections in photochemical and photobiological processes.
The models of vibronic quantum dynamics are adapted from original work by S. Hahn and G. Stock.
One-dimensional model
The simplest model involves two electronic states vibronically coupled by a collective reaction coordinate describing the isomerization process. The corresponding potential energy curves exhibit two avoided crossings giving rise to nonadiabatic processes.
Two-dimensional model
In a two-dimensional model, the role of the remaining vibrational degrees of freedom is modelled by a single, effective mode resembling the ethylene C=C stretching coordinate. The corresponding potential energy curves exhibit two conical intersections giving rise to nonadiabatic processes.
