Quantum coherent π-electron rotations in a non-planar chiral molecule induced by using a linearly polarized UV laser pulse

H Mineo ,Y Fujimura

doi:10.1088/1742-6596/627/1/012020

Abstract

We propose an ultrafast quantum switching method of π-electron rotations, which are switched among four rotational patterns in a nonplanar chiral aromatic molecule (P)-2,2’- biphenol and perform the sequential switching among four rotational patterns which are performed by the overlapped pump-dump laser pulses. Coherent π-electron dynamics are generated by applying the linearly polarized UV pulse laser to create a pair of coherent quasidegenerated excited states. We also plot the time-dependent π-electron ring current, and discussed ring current transfer between two aromatic rings.

Highlights

Organic electronics and devices have been actively studied [1,2,3,4,5,6,7,8] because of its potential usefulness
Here we first show the results of the -electron ring current generated on the (P)-2,2’ biphenol, and demonstrate two-dimenional ultrafast quantum switching of the angular momentum
It is observed that ring currents JL and JR oscillate in the same phase, whereas the bridge bond current JB is permanently zero

Summary

Introduction

Organic electronics and devices have been actively studied [1,2,3,4,5,6,7,8] because of its potential usefulness. The degenerated electronic states are excited by using the circularly polarized UV laser pulses. The rotational direction of the resultant “incoherent” -electron ring current depends on whether the right or left circularly polarized laser pulse is applied, and the current is unidirectional. On the other hand the linearly polarized UV laser pulses can create a “coherent” -electron ring current in a chiral aromatic molecule with lower symmetry. Kanno et al carried out numerical simulations of the -electron rotation for 2,5-dichloro[n](3,6) pyrazinophane [11, 12], which is a planar chiral aromatic molecule. The rotational direction of -electron ring current is determined by whether the superposition of quasi-degenerate coherent states excited by linearly polarized UV laser pulse is in-phase or out-phase. The results of numerical simulation indicates that the chiral aromatic molecule can be a candidate of the ultrafast switching device

Methods

Results

Conclusion