An experimental and theoretical study on the states of PHBA in aqueous solution

A high quality Raman spectrum of p-hydroxybenzoic acid (PHBA) aqueous solution (10−2 M) under ultraviolet (UV) excitation at 325 nm was obtained, which could not be observed with visible and near infrared (NIR) excitations due to the low concentration in aqueous solution. Theoretical calculated Raman frequencies based on density functional theory (DFT) reveals well the states of PHBA in aqueous solution. We supply a new method for studying the behaviors of materials in solution.