The study concludes that Density Functional Theory (DFT) is significantly more effective than the Hartree-Fock (HF) method in identifying and analyzing the molecular structures and functional groups of TCBD isomers. DFT's ability to account for electron correlation effects and generate more distinct and consistent peaks across isomers underscores its superiority. While HF struggles to detect certain functional groups, DFT accurately identifies the vibrational frequencies of all relevant bonds, particularly C-H and C-Cl stretches. The results align with existing literature, further validating the robustness of DFT as a computational tool for studying complex molecular systems. However, the overlapping of IR peaks indicates that future research could benefit from incorporating other techniques, such as NMR or Raman spectroscopy, to fully differentiate between isomers. Ultimately, the findings emphasize the importance of using advanced DFT methods for accurate molecular characterization in environmental chemistry and beyond.