McGill.CA / Science / Department of Physics

CPM Seminar

Absorption of solar radiation by hydrogen-bonded complexes

W. Geldart

The excitation spectrum and optical response properties can be quite complex in systems where weak hydrogen bonds play a significant role. The liquid and solid phases of H20 and the low temperature properties of ferroelectrics such as KDP are familiar examples in condensed states. The properties of small hydrogen-bonded molecular complexes (H2O-H2O, H2O-O2, H2O-N2, etc) are less well known. At the present time there is a disagreement between observations and theory of about 25% regarding the absorption of incoming solar radiation by the atmosphere (under cloudy sky conditions), and it has been suggested that water dimers (and related complexes) may be relevant. The current experimental situation will be reviewed and a recent calculation of the cross-section for the absorption of radiation by (H2O)2 dimers will be outlined and compared with the observational data. Significant puzzles remain.

Chylek and Geldart, Geophys. Res.. Lett. 24, 2015 (1997)
Tso, Geldart and Chylek, J. Chem. Phys. 108, 5319 (1998)

Thursday, October 22nd 1998, 15:30
Ernest Rutherford Physics Building, room 114