DFT DFT calculations Fourier transform infrared (FTIR) frequencies HSAB principle Pyrophosphate Quercetin molecule RRKM theory Research & information: general Science: general issues [NiFeSe] hydrogenase antibiotics antimicrobials antioxidants bacterial infections biofilms chemical kinetics chemical reactivity theory concerted rotation of the hydroxyl groups condensed phase conformational mobility coordination complexes depressive disorder dispersion donor-acceptor systems electronic structure first-principles calculations fluoxetine free radical scavengers hydroxyl group information theory