Second-order polarizabilities of nitropyridine derivatives determined with electric-field-induced second-harmonic generation and a solvatochromic method: A comparative study

Abstract

A comparison is made between the second-order polarizabilities of nitropyridine derivatives determined with two different methods: electric-field-induced second-harmonic generation (EFISH) and a solvatochromic method. Both techniques yield the same values within the experimental errors, showing that the main contribution of the microscopic nonlinearity arises from a single intramolecular charge-transfer transition. Based on the quantum-mechanical two-level model, the solvatochromic method also yields important molecular parameters, such as transition and excited-state dipole moments. The second-order polarizabilities determined with the EFISH method are shown to follow the theoretical two-level dispersion.