Quantum control of molecular chirality: Ab initio molecular orbital study and wave packet analysis of l,l′-binaphthyl

The results of a theoretical study on quantum control of an axial chirality change reaction in l,l′-binaphthyl are presented. The chiral change from the P form to the M form via the third excited electronic state has been considered, the pure enantiomer of the P-form being assumed as the initial state. Asymmetric double-well potential energy surfaces of the ground state (S0) and the third excited electronic state (S3) and the corresponding transition moment along the reaction coordinate were evaluated using ab initio MO methods. An optimal control theory was applied to the chirality change reaction. The results of the quantum control showed that motions of nuclear wavepackets on both the S0 and S3 reaction coordinates were controlled. The mechanism of the quantum control is explained as a sequence of quantum transitions between S0 and S3, and the control is performed by irradiating a sequence of a pump-dump pulse.