The geometry of a typical polymethine dye is tuned as a function of an external electric field from a neutral structure to a zwitterionic (charge-separated) structure. The corresponding evolutions of the ground and excited states and the nonlinear optical response are calculated at the correlated level. Analysis of the results allows us to determine a consistent three-term model for the second hyperpolarizability. This model rationalizes recent experimental data and can be exploited to optimize γ in either a positive or negative sense.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry