The asymmetric cage structure of (H2O)7 from a combined spectroscopic and computational study

Abstract

The vibrational OH stretch spectra have been measured for the size-selected pure water clusters (H2O)7. In contrast to (H2O)n, n=8–10 clusters, which exhibit three distinct bands corresponding to three distinct types of OH bonds, the heptamer spectrum displays seven bands spanning the range from 2935 to 3720 cm−1. Calculations suggest that the spectra originate from two isomers, derived from the S4 octamer cube by removal of either one double donor or one double acceptor water molecule.