Investigation of NLO properties of substituted ( M )‐tetrathia‐[7]‐helicenes by semiempirical and DFT methods

In this article, we propose a theoretical study of static and dynamic polarizability α, first hyperpolarizability β, and second hyperpolarizability γ of substituted ( M )‐tetrathia‐[7]‐helicenes. Both a semiempirical approach, in the case of static and dynamic properties, and density functional theory, in the case of static electric properties, were used. The nonlinear optical (NLO) properties of a set of 10 molecules were investigated to predict the couple of donor–acceptor substituents that could best enhance the optical properties of ( M )‐tetrathia‐[7]‐helicene. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003