Molecules with multi-directional charge-transfer (MDCT) transitions as promising chromophores for third order nonlinear optics

Based on quantum chemical calculations molecules with multi-directional charge-transfer (MDCT) transitions are shown to posses values of the 2. molecular hyperpolarizability, γ, significantly larger than their uni-directional charge-transfer (UDCT) analogues. Very interestingly the calculated linear optical properties shows no redshifts of the CT transitions on going from a UDCT molecule to the MDCT analogues having the same length of the donor-acceptor moiety. This finding is important in the context of optimized figure of merits/transparency trade-off.