521. Dissociation of HNO₃ in Water Revisited: Experiment and Theory

Ipek Munar, Melike Özkan Özer, Edoardo Fusco, Deniz Uner, Viktorya Aviyente, Michael Bühl, PCCP, (2024), DOI: 10.1039/D4CP01667J

Nitric acid dissociation in water is studied as a function of concentration, employing experimental techniques (1H NMR, calorimetry), quantum chemical methods (B3LYP and PBE functionals for molecular clusters) and molecular dynamics simulations (PBE-D3 functional for solutions under periodic boundary conditions). The extent of dissociation, via proton transfer to a neighboring water molecule, as a function of concentration is studied computationally for molecular nitric acid clusters HNO3(H2O)x (x = 1 - 8), as well as periodic liquids (HNO3 mole fractions 0.19 and 0.5, simulated at T = 300 K and 450 K). Despite the simple nature of these structural models, their computed and simulated average 1H chemical shifts compare well with the experimental measurements in this study. Finally the measured and calculated chemical shifts have shown reasonable relationships with the enthalpy change upon mixing of this binary complex.