Inverse Molecular Design in a Tight-Binding Framework

The number of chemical species of modest molecular weight that can be accessed with known synthetic methods is astronomical. An open challenge is to explore this space in a manner that will enable the discovery of molecular species and materials that exhibit optimized properties. Recently, a strategy was developed to perform continuous optimization of molecular properties, the linear combination of atomic potentials (LCAP) approach.$^{1}$ Here, using a simple tight-binding (TB) implementation, we show that the LCAP strategy can successfully explore vast chemical libraries that are based on planar $\pi $-electron motifs. We show that LCAP property optimization of $\pi $-electron polarizabilities and hyperpolarizabilities is effective for libraries with 10$^{4}$ to 10$^{16}$ members. This approach finds optimal structures among 10$^{4}$ candidates with about 40 individual molecular property calculations. As such, for molecular candidates with strong structural similarity, the TB-LCAP approach may provide an effective means of identifying structures with optimal properties. \newline $^{1}$M. Wang, X. Hu, D. N. Beratan, and W. Yang, J. Am. Chem. Soc. \textbf{128}, 3228 (2006); S. Keinan, X. Hu, D. N. Beratan, and W. Yang, J. Phys. Chem. A \textbf{111}, 176 (2007).