Localization of an excess electron in water clusters

Simulation of e−–(H20)n for n=1,2,3 done at 5 K, using path integral Monte Carlo methods shows that a water dimer as well as a water trimer in the linear configuration can bind an electron in a diffuse surface state. The binding energy of the electron dimer and the electron trimer is estimated to be between 3–6 and 4–9 meV, respectively. The results indicate that the electron does not alter the structure of the water dimer but does induce observable changes in the water trimer. It is also shown that an electron does not bind to a monomer. These results are discussed in connection with recent molecular beam experiments.