Effect of Molecular Polarization on Bond-Length Alternation, Linear Polarizability, First and Second Hyperpolarizability in Donor-Acceptor Polyenes as a Function of Chain Length

摘要: The linear (α) and nonlinear (β, γ) molecular polarizabilities of a series donor-acceptor polyenes containing 3-8 π-bonds are studied using the semiempirical AMl parametrization and finite-field (hyper)polarizability computations as function polarization and resulting changes in bond-length alternation. Plots α, β, γ versus bond length alternation had similar shapes (although different magnitudes) for each chain length. The changes with length were fit to exponential functions (N^m) various bond-length alternations. These values varied over significant range depending upon the value alternation chosen.