How the Shape of an H-Bonded Network Controls Proton-Coupled Water Activation in HONO Formation

It's the Network Numerous reactions of small molecules and ions in the atmosphere take place in the confines of watery aerosols. Relph et al. (p. 308 ; see the Perspective by Siefermann and Abel ) explored the specific influence of a water cluster's geometry on the transformation of solvated nitrosonium (NO + ) to nitrous acid (HONO). The reaction involves (O)N–O(H) bond formation with one water molecule, concomitant with proton transfer to additional, surrounding water molecules. Vibrational spectroscopy and theoretical simulations suggest that certain arrangements of the surrounding water network are much more effective than others in accommodating this charge transfer, and thus facilitating the reaction.