Measurement of quantum tunneling between chiral isomers of the cyclic water trimer

Science  25 Sep 1992:
Vol. 257, Issue 5078, pp. 1937-1940
DOI: 10.1126/science.1411509


A detailed experimental study of the water trimer is reported. A vibration-rotation-tunneling band of the perdeuterated cluster has been measured near 89.6 wave numbers by tunable far infrared laser absorption spectroscopy. The data indicate a chiral six-membered ring structure with rapid quantum tunneling occurring between the enantiomers. The observed vibration involves torsional motion of the water subunits about each hydrogen bond axis. It is speculated that larger water clusters would also exhibit transient chirality and that similar effects may be found in liquid water.