Quantifying hydrogen bond cooperativity in water:  VRT spectroscopy of the water tetramer.
Measurement of the far-infrared vibration-rotation tunneling spectrum of the perdeuterated water tetramer is described.  Precisely determined rotational constants and relative intensity measurements indicate a cyclic quasi-planar minimum energy structure, which is in agreement with recent ab initio calculations.  The O-O separation deduced from the data indicates a rapid exponential convergence to the ordered bulk value with increasing cluster size.  Observed quantum tunneling splittings are interpreted in terms of hydrogen bond rearrangements connecting two degenerate structures.
Cruzan
J D
JD
Department of Chemistry, University of California at Berkeley 94720, USA.
Braly
L B
LB
Liu
K
K
Brown
M G
MG
Loeser
J G
JG
Saykally
R J
RJ
D017666:Deuterium Oxide / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D008956:Models, Chemical; D010100:Oxygen / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D019265:Spectroscopy, Near-Infrared; D014867:Water / Q000737:chemistry*
D014867:Water; D006859:Hydrogen; D017666:Deuterium Oxide; D010100:Oxygen