Chemical Physics Letters, Vol.497, No.1-3, 76-80, 2010
Electronic and optical features of N,N'-bis(4-aminophenyl)1,4-quinonenediimine doped with silicotungsten polyacid: Experimental and numerical studies
N,N'-Bis(4-aminophenyl)1,4-quinonenediimine doped with silicotungsten polyacid were investigated by Raman, IR and UV-Vis absorption methods and the results analyzed based on numerical approaches. In this aim, density functional theory (DFT) calculations were performed to optimize the geometry and to clarify the electronic and optical features of the investigated molecules. Three main systems were considered and consist in a conjugated organic group N,N'-bis(4-aminophenyl)1,4-quinonenediimine, a silicotungsten polyacid group and an association of these molecules taken in their ground state. Theoretical models with functionals based on judicious choice of potentials and exchange interactions were implemented in the calculation routines in order to achieve consistent analysis of the experimental results. As a consequence, Hartree-Fock (HF) exchange term in the hybrid functional leads to different organic group conformations while the DFT/B3LYP potential reproduces the main features of the experimental IR spectra. The time dependant TD-DFT was used in order to calculate the characteristic electronic transitions of the considered molecules and the results compared with the experimental values. (C) 2010 Elsevier B.V. All rights reserved.