Communication: Charge transfer dominates over proton transfer in the reaction of nitric acid with gas-phase hydrated electrons

The reaction of HNO(3) with hydrated electrons (H(2)O)(n)(-) (n = 35-65) in the gas phase was studied using Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry and ab initio molecular dynamics simulations. Kinetic analysis of the experimental data shows that OH(-)(H(2)O)(m) is formed primarily via a reaction of the hydrated electron with HNO(3) inside the cluster, while proton transfer is not observed and NO(3)(-)(H(2)O)(m) is just a secondary product. The reaction enthalpy was determined using nanocalorimetry, revealing a quite exothermic charge transfer with -241 ± 69 kJ mol(-1). Ab initio molecular dynamics simulations indicate that proton transfer is an allowed reaction pathway, but the overall thermochemistry favors charge transfer.