Solvent Effects on Electronic Absorption

A combined experimental and theoretical experiment examining the solvent-dependent electronic transitions of two dye molecules is reported. Experimentally the solvatochromic shifts are measured for Michler’s ketone and Reichardt’s dye. The experimental electronic spectra are considered in the context of solvent properties and quantum calculations of the dyes. Comparisons are made between different levels of theories, and molecular orbitals involved in the spectral transitions are visualized. Coupling computational and spectroscopic methods allows for a comprehensive analysis of the solvent-solute interactions by providing both bulk and molecular level pictures of the chemical system. This experiment is designed for an upper level physical chemistry laboratory.