Henning Meyer of the University of Georgia is supported by the Experimental Physical Chemistry Program and the Office of Multidisciplinary Activities to investigate the structure and dynamics of van der Waals complexes using high resolution near infrared spectroscopy in combination with counterpropagating pulsed molecular beam scattering. The van der Waals complexes to be studied contain an infrared chromophore and a monomer amenable to state-specific multiphoton ionization. Thus vibrational excitation of the monomer can result in predissociation of the complex, and by detecting the fragments, Meyer will measure fundamental and overtone cluster bands with rotational resolution. From these measurements, he will gain information on the fragment velocity and angular momentum anisotropies as well as the state correlation, the dissociation energy of the complex, and state-specific cross sections for the monomers. Ultimately, from these experiments he will derive the multidimensional potential energy surface. The PI will carry out a parallel theoretical effort: ab-initio electronic structure calculations and quantum mechanical solutions to the bound state and scattering problems. The interest in molecular clusters has been motivated largely by the prospect of developing a more detailed understanding of bulk matter through the access to direct quantum specific information on finite sized cluster systems. Dimers are of particular importance as the first step towards describing bulk material at a molecular level. Their structure and dynamics can be described in terms of a multidimensional potential energy surface which is crucial to a variety of very active research areas like the molecular modeling of solvent effects and biomolecules. The concept of a potential energy surface is also the basis for the theoretical description of bimolecular reactions and vibrational energy transfer, and therefore it plays a key role in the modeling of such diverse gas phase processes as combustion, atmospheric warming and pollution due to the release of man-made substances.
