Resolving the optical spectrum of water: coordination and electrostatic effects.
The optical absorption of small water clusters, water chains, liquid water, and crystalline ice is analyzed computationally. We identify two competing mechanisms determining the onset of the optical absorption: Electronic transitions involving surface molecules of finite clusters or chains cause a redshift upon molecular aggregation compared to monomers. On the other hand, a strong blueshift is caused by the electrostatic environment experienced by water monomers embedded in a hydrate shell. Concerning the recent dispute over the structure of the liquid, the present results support the conventional fourfold coordinated water, as obtained from ab initio molecular-dynamics simulations.
Centre of Theoretical Chemistry and Physics, The New Zealand Institute for Advanced Study, Massey University Auckland, North Shore City, 0745 Auckland, New Zealand.
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A
Hermann
W G
WG
Schmidt
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P
Schwerdtfeger
D006860:Hydrogen Bonding; D007053:Ice; D008958:Models, Molecular; D013057:Spectrum Analysis / Q000379:methods; D055672:Static Electricity; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
D007053:Ice; D014867:Water