Theoretical and experimental investigation of UV–Vis absorption spectra in plasma-activated water

This research comprehensively examines the physicochemical and optical properties of plasma-activated water (PAW) produced by a serially associated dielectric barrier discharge (DBD) and gliding arc plasma jet (GAPJ) system. Experimental UV–Vis spectroscopy identified prominent absorption bands attributed to reactive oxygen and nitrogen species (RONS) such as nitrite (NO2−), nitrate (NO3−), hydrogen peroxide (H2O2), nitrous acid (HNO2), and nitric acid (HNO3). To precisely interpret the complex and overlapping experimental spectra, density functional theory (DFT) simulations were utilized to model electronic transitions. These theoretical findings crucially revealed the influence of protonation on the optical features, showing blue-shifted bands for ionic species and red-shifted bands for their protonated forms.Graphic abstractIntegrated UV-Vis and TD-DFT analysis of Plasma-Activated Water (PAW) from a serial DBD-GAPJ system, highlighting the decisive influence of protonation on the optical features of RONS