Excited State Absorption from Real-Time Time-Dependent Density Functional Theory: Optical Limiting in Zinc Phthalocyanine

Fischer, S. A.; Cramer, C. J.; Govind, N.
J. Phys. Chem. Lett. 2016, 7, 1387 (doi:10.1021/acs.jpclett.6b00282).

Optical limiting materials are capable of attenuating light in order to protect delicate equipment from high intensity light sources. Phthalocyanines have attracted a lot of attention for optical limiting applications due to their versatility and large nonlinear absorption. With excited state absorption (ESA) being the primary mechanism for optical limiting behavior in phthalocyanines, the ability to tune the optical absorption of ground and excited states in phthalocyanines would allow for the development of advanced optical limiters. We recently developed a method for the calculation of ESA based on real-time time-dependent density functional theory propagation of an excited state density. In this work we apply the approach to zinc phthalocyanine, demonstrating the ability of our method to eciently identify the optical limiting potential of a molecular complex.