Development and Application of Density Functional Theory in Design of Two-Photon Absorbing Photochromic Materials for Optical Data Storage
Diarylethenes are able to undergo light-induced transition from the open to closed ring isomer (photocyclization) accompanied by the change in optical properties (photochromism). This ability holds a great promise for photonic applications, including optical data storage and ultrafast optical switching. Photocyclization initiated by two photon absorption (2PA) could drastically increase the density of these devices. We analyze the Kohn-Sham orbitals responsible for photocyclization, and suggest the molecular structures that are expected to have both 2PA and photochromic activity. The proposed modifications are validated using the potential energy surfaces of the excited states and two-photon absorbing profiles, predicted using Time-Dependent Density Functional Theory (TD-DFT).