Experimental and theoretical investigation of spectroscopic properties of some benzoic acid derivaties

In this study, molecular structure and vibration frequency analysis of 4-(4-Methoxyphenoxy) benzoic acid and 4-(4-Hydroxyphenoxy) benzoic acid were studied. Both molecules were worked with an experimentally and theoretically. Firstly step FT-IR spectra of molecules were recorded between 4000-400 cm-1, FT-Raman spectrums were recorded between 4000-50 cm-1. Theoretical and experimental IR and Raman spectra were figured. Bond angles, bond lenghts and vibration frequencies of the two molecules were calculated with denstiy function theory and B3LYP/6-311++G(d,p) basis set by Gaussian 03 program and their values which scaled compared with experimental values. Total energy distribution (TED) were done to find the vibration modes and scaled quantum mechanics (SQM) program was used for this applications. Secondly, after determining electronic transitions by using UV spectroscopy for 4-4MPBA molecule, the wavelengths corresponding to these transitions were calculated. Additionally the excited energy values, the highest occupied molecular (HOMO) orbital, the lowest unoccupied molecular orbital (LUMO) energy values and dipol moment were determined.