Electron bound to hydrated hydrogen fluoric acids

Electron(e)-binding hydrated hydrogen fluoride clusters [e-HF(H2O)n=1-10] have been studied with density functional and ab intio calculations. The hydrofluoric acid in e-HF(H2O)n clusters is found to be undissociated at 0 K till n = 10. The e-HF(H2O)3 cluster is particularly unstable compared with the corresponding neutral structures, which reflects the particularly unstable antimagic number of e-water tetramer. The characteristic of “magic” numbers of electron-water clusters appears in these e-(HF)(H2O)n clusters. The vertical detachment energies of e-HF(H2O)n are enhanced by the HF acid as compared with those of the e-binding water clusters [e-(H2O)n + 1], and the excess electron is surface bound near the terminal water molecule with two dangling hydrogen atoms. The coordination number of HF is one for n = 1-4 as a linear structure in contrast to two for n = 5-6, and three for n = 7-10. The phase transition from 2- to 3-dimensional structures appears at penta-hydrated system in contrast to hepta-hydrated system for neutral HF-water clusters. The structures for e-HF(H2O)n=2,3 are quite different from those of the corresponding e-(H2O)n + 1 = 3,4, and the structures for e-HF(H2O)n = 2-6 are quite different from those of the corresponding HF(H2O)n = 2-6.