GEOMETRY, VIBRATIONAL, NBO, MEP AND HOMO-LUMO ANALYSIS OF TETRAHYDROFURAN (THF) BASED ON DFT CALCULATIONS

Tóm tắt

In this paper, the density functional theoretical (DFT) computations were performed at the B3LYP level with the basis set 6-311++G(2d,2p) to derive the optimized geometry, vibrational wavenumbers. The fundamental vibrations were assigned on the basis of the potential energy distribution (PED) of the vibrational modes, calculated with VEDA program. In addition, the molecular orbital calculations, such as Nutural Bond Orbital (NBO), HOMO-LUMO energy gap and Molecular Electrostatic Potential (MEP) surfaces, were also performed with the same level of DFT. Effective second-order perturbation interaction energy E(2) connected with the interaction between electron donors and electron acceptors was determined by the NBO analysis. The energy gap of HOMO–LUMO orbitals (ΔEHOMO-LUMO) has been found 6.558 eV. Some essential vibrational characteristics namely C–H stretch, C–H scissoring and twisting of the molecule, have also been analyzed and compared with the previously reported ab initio data and with the experimental.