Dynamics of Electronically Excited States: Models for Chemical Reactivity

University Of Pittsburgh, Pittsburgh PA

Investigators

Abstract

Professor David Pratt of the University of Pittsburgh is supported by the Experimental Physical Chemistry program to perform high resolution electronic spectroscopy on molecules and solvated molecules in molecular beams. The high resolution spectroscopy provides structural details that reveal fundamental information about low barrier intramolecular hydrogen bonds, chiral identification and solvent reorganization in the gas phase. Some of the systems proposed in this study include benzene-water and the benzene dimer, weakly bound complexes of enantiomers, and twisted internal charge transfer molecules. The methods include supersonic expansion, continuous wave molecular beams, frequency-doubled tunable single frequency lasers, spatially selective fluorescence detection and high speed data acquisition. Unparalleled resolution is obtained approaching 1 MHz in the ultraviolet. High resolution spectroscopy can provide the "final word" on debates that arise from low-resolution spectroscopy experiments, and thus serve as benchmark measurements for the identification of the structures some gas phase species and complexes. The bonding of molecular complexes can provide insight on how molecules recognize each other, and can improve the design, for example, of separation media for chiral purification of drugs. Electronic spectroscopy is a mature field, however, Pratt's type of work is only performed by several groups in the world. Pratt continues to build collaborative ties to research groups at smaller universities in the US, industrial and government labs, and at universities abroad.