Absorption anisotropy studies of polymethine dyes

Abstract

The determination of the spectral position of the excited states and orientation of the transition dipole moments of polymethine molecules is experimentally measured using two methods: the steady-state fluorescence anisotropy method, and a two-color polar¬ization-resolved pump-probe method. This novel use of the pump-probe method is described in detail and a comparison to the flu¬orescence method is given. Quantum-chemical modeling on the effects of the bridge structure in the polymethine chromophore on the linear absorption spectrum is also discussed.