Two-dimensional optical spectroscopy: Two-color photon echoes of electronically coupled phthalocyanine dimers.

Two-color photon echo peak shift spectroscopy was used to study electronic coupling in a phthalocyanine homodimer. Two optical parametric amplifiers were used to produce pulses to excite the split lower states of LuPc[sub 2][sup -]. The existence of a two-color peak shift indicates the existence of correlation between these two dipole-allowed states. The nature of this correlation is discussed based on theoretical predictions of the interactions between exciton and charge resonance states. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]