Density functional theory and FTIR spectroscopic study of carboxyl group

Both molecular modelling and FTIR have been used to study carboxyl group among acetic acid, potassium and sodium acetate, glycine, sodium salicylate, salicylic acid and cellulose acetate. Molecular modelling was used to study formic acid. carhoxylic acids R-COOH, monovalent alkali carboxylate CH 3 COO-M, alanine, benzoic acid as well as naphthalene. Each structure was optimized using VWN/DZVP then vibrational spectra were further calculated at the same level of theory. The comparison between both calculated and experimental spectra showed good agreement with each other. Except for formic acid and free carboxyl, the characteristic band is shifted towards lower frequency.