title: Optimal control of ultrafast cis-trans photoisomerization of retinal in rhodopsin via a conical intersection.
abstract: Optimal control simulation is applied to the cis-trans photoisomerization of retinal in rhodopsin within a two-dimensional, two-electronic-state model with a conical intersection [S. Hahn and G. Stock, J. Phys. Chem. B 104, 1146 (2000)]. For this case study, we investigate coherent control mechanisms, in which laser pulses work cooperatively with a conical intersection that acts as a "wave-packet cannon." Optimally designed pulses largely consist of shaping subpulses that prepare a wave packet, which is localized along a reaction coordinate and has little energy in the coupling mode, through multiple electronic transitions. This shaping process is shown to be essential for achieving a high target yield although the envelopes of the calculated pulses depend on the local topography of the potential-energy surfaces around the conical intersection and the choice of target. The control mechanisms are analyzed by considering the motion of reduced wave packets in a nuclear configuration space as well as by snapshots of probability current-density maps.
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Abe
authors.forename: Yukiyoshi
authors.initials: Y
authors.lastname: Ohtsuki
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Fujimura
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Domcke