Spectroscopic and DFT Studies of Calix[4]arene: Time-dependent DFT Calculations for Elucidating the Variation in the Excitation Energies with Geometry

Abstract

We have searched low-lying conformers of calix[4]arene and found one global minimum having a cone shape, together with three conformers such as partial cone-shape conformers. We then elucidated the thermodynamics for the conformational changes by performing density-functional theory (DFT) calculations. The time-dependent DFT calculation enabled us to assign the absorption spectrum and to reveal a variation of the excitation energies with geometry.