Title: New insight into the dynamics of rhodopsin photoisomerization from one-dimensional quantum-classical modeling,
Abstract: Characterization of the primary events involved in the $cis-trans$
photoisomerization of the rhodopsin retinal chromophore was approximated by a
minimum one-dimensional quantum-classical model. The developed mathematical
model is identical to that obtained using conventional quantum-classical
approaches, and multiparametric quantum-chemical or molecular dynamics (MD)
computations were not required. The quantum subsystem of the model includes
three electronic states for rhodopsin: (i) the ground state, (ii) the excited
state, and (iii) the primary photoproduct in the ground state. The resultant
model is in perfect agreement with experimental data in terms of the quantum
yield, the time required to reach the conical intersection and to complete the
quantum evolution, the range of the characteristic low frequencies active
within the primary events of the $11-cis$ retinal isomerization, and the
coherent character of the photoreaction. An effective redistribution of excess
energy between the vibration modes of rhodopsin was revealed by analysis of the
dissipation process. The results confirm the validity of the minimal model,
despite its one-dimensional character. The fundamental nature of the
photoreaction was therefore demonstrated using a minimum mathematical model for
the first time.