Picosecond Studies of Chemical Intermediates
Final technical rept. Nov 1983-Mar 1991,
COLUMBIA UNIV NEW YORK DEPT OF CHEMISTRY
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Surface second harmonic generation SSHG has been used to study the chemical and physical properties of liquid interfaces. Information about the thermodynamics of neat liquid surfaces has been found by observing the SH signal as a function of temperature. Extensive studies using monolayers at the air water interface have been undertaken. Studies of acidbase equilibrium and monolayer phase transitions have been performed. The gas-liquid coexistence region and an orientational phase transition has been observed. SHG was used to study the interface properties of fused silicaelectrolyte solution. Orientational relaxation has been observed on the picosecond time scale at the airwater interface by time-resolved second harmonic generation. The data suggests that the ground and excited state of Rhodamine 6G have different equilibrium orientational distributions. Femtosecond studies of electrons in liquids have characterized the geminate recombination and solvation dynamics of electrons in polar and nonpolar liquids. Photodetachment of electrons from halide ions in aqueous solution has also been studies. Picosecond studies of chemical intermediates have examined the role of restricted geometries on elementary chemical processes.
- Physical Chemistry