Ultimately, the study's findings underscore the utility of hybrid DFT functionals like B3LYP and dispersioncorrected functionals like B3LYP-D3BJ in predicting molecular geometries and vibrational spectra with a high degree of accuracy. This methodological approach allowed for a comprehensive and detailed understanding of the structural properties of the TCBD isomers, thereby contributing to the broader field of computational chemistry and molecular spectroscopy.