Abstract:

This study presents a computational chemistry experiment designed for junior undergraduates majoring in chemistry in the structural chemistry course, focusing on the discoloration principle of phenolphthalein indicator. The experiment serves as a fundamental investigation into discoloration reactions in the inorganic chemistry course. By employing the Gaussian program, the discoloration processes of phenolphthalein are explored. Through the analysis of macroscopic phenomena, such as changes in UV-Vis absorption spectra before and after discoloration, students gain insights into the mechanism of phenolphthalein discoloration from various microscopic perspectives. Additionally, the "class-micro-topic-flipped classroom" approach is employed to foster scientific innovation by incorporating knowledge extension training.

Key words: Phenolphthalein indicator, UV-Vis absorption spectrum, Geometric structure, Natural population analysis (NPA) charge, Natural bond orbital (NBO)