Electric Field Simulation of Substituents in Donor−Acceptor Polyenes: A Comparison with Ab Initio Predictions for Dipole Moments, Polarizabilities, and Hyperpolarizabilities

The treatment of dipole moments (μ), polarizabilities (α), and hyperpolarizabilities (β, γ) in push−pull systems using electric field simulation for the substituents is reanalyzed and tested by comparison with ab initio Hartree−Fock calculations on representative donor−acceptor (D/A) polyenes. Both vibrational and electronic contributions are properly taken into account. We find that the field simulation approach can be applied semiquantitatively to relate the odd-order (μ, β) properties only. Even for these properties, however, features such as the chain-length dependence cannot be reproduced due to the excessively delocalized description of the D/A substituents.