Theoretical study of structure and spectra of cage clusters (H2O)n, n=11,12

The optimal structures, interaction energies and OH stretch frequencies of water cage clusters, (H2O)n, n=11,12 have been investigated, employing an empirical polarizable potential and MP2 ab initio calculations. The new spectral feature at the OH stretch region for (H2O)12 clusters in comparison with the octamer is the presence of new border spectral lines due to four-coordinated double donor–double acceptor (DDAA) water molecules (D-donor, A-acceptor) in the gap between the two distinct relatively narrow spectral range corresponding, as in the octamer, to double donor–single acceptor (DDA) and single donor–double acceptor (DAA) water molecules.