In this work, the geometric, electronic, vibrational, and thermodynamic properties of the bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) molecule, used as an important donor in the chemistry of organic molecular conductors, were investigated within the framework of density functional theory (DFT). The calculations were performed using the ORCA 6.0 program at the PBE0/def2-TZVP level with the D3BJ dispersion correction. The absence of negative vibrational frequencies in the optimized structure indicates that it corresponds to a local minimum on the potential energy surface. For the frontier molecular orbitals, the HOMO and LUMO energies were −4.955 and −0.955 eV, respectively, while the Kohn–Sham HOMO–LUMO energy difference was ≈4.01 eV. Mulliken charges and Mayer bond orders showed the delocalized character of the electron density in the molecular core. In the calculated IR spectrum, the modes in the regions of 810.93, 1323.38, and 1583.55 cm⁻¹ were identified as characteristic vibrations. At a temperature of 298.15 K and a pressure of 101.325 kPa, the Gibbs free energy was −3570.00008156 Eh. The obtained results characterize the features of the electronic structure of the neutral BEDT-TTF molecule in the isolated state and provide a theoretical basis for discussing its donor nature at the molecular level.
Investigation of The Geometric, Electronic, Vibrational, And Thermodynamic Properties of the BEDT-TTF Molecule Using the DFT Method
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References
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