Experimental (UV-Raman) and theoretical (DFT) study of pyridine carboxylic acid in aqueous solution

High quality Raman spectrum of pyridine carboxylic acid in aqueous solution under ultraviolet (UV) excitation at 325 nm was obtained. Some conspicuous changes of UV-Raman spectra accompanied with the pH variation indicate the different molecule structure. Theoretical calculated Raman frequencies based on density functional theory (DFT) reveals well the different states of pyridine carboxylic acid in aqueous solution.