Structures and energetics of proton-bound formic acid—water clusters, (HCOOH)_n(H_2O)H~+

摘要

Semiempirical and ab initio calculations have been performed on proton-bound mixed clusters (HCOOH)n(H2O)H+ with n = 1–8. Energetically competitive structures were deduced: open-chain structures with a H2O unit at the end are favored energetically for lower members (n < 4) of the cluster series, nucleation around H3O+ begins at n = 4 and chains terminated by cyclic dimer units with H3O+ at the center are favored for n = 5–8. Ring closure around H3O+ and dimer formation begins at n = 5.