Theoretical investigation of the second-order nonlinear optical properties of calix[4]arene molecules

Summary form only given. We investigate theoretically the second-order nonlinear optical properties of a new class of compounds presenting more than one [Donor/spl pi/ conjugated segment-Acceptor] unit in a single molecule: the calix[4]arenes. We calculate the second-order polarizabilities /spl beta/ for four conformers of calix[4]arenes, namely, the cone, partial cone, 1, 2 alternate and 1, 3 alternate conformations. The theoretical results are compared with Electric-Field-Induced Second Harmonic Generation (EFISGH) and Hyper Rayleigh Scattering (HRS) experimental data. We describe the evolution of the /spl beta/ response with the change of conformation and we point out the presence of strong /spl pi/ - /spl pi/ cofacial interactions (which shift the charge transfer bands to shorter wavelengths making these calix[4]arenes promising compounds for applications in frequency doubling).