Quantum mechanical assessment on the optical properties of capsanthin conformers

Abstract

AbstractAs optical properties, the ultraviolet–visible (UV–Vis) absorption spectra of capsanthin‐based red natural dye are a decisive parameter for their usage in various applications. Thus, accurately predicting the maximum UV–Vis wavelength () values is critical in designing dye‐conjugated material. Extensive metadynamics simulations were carried out to generate capsanthin conformers at various levels of the extended tight‐binding method. Benchmarking the time‐dependent density‐functional theory (TD‐DFT) methods help understand the results of a particular functional and allows a comparison between results obtained with different functional. The long‐range correction (LC) scheme in LC‐TD‐DFT‐D4/ωB97X/def2‐SVP has been found to reproduce the experimental and exhibited the effect of conformational changes to the calculated wavelengths. On the other hand, an inexpensive yet efficient LC‐TD‐DFTB method reproduced the experimental insensitive to conformational changes.