James Baird
Professor:
Chemistry
Phone: +1 401 863 3325
Phone 2: +1 401 863 3392
james_baird@brown.edu
There is a great interest in understanding processes occurring in the ground and excited states of both atoms and molecules. Professor Baird's research in chemical physics involves studies of energy and state transfer collisions, as well as measurement of energy level separations, in simple molecular and atomic species. For example, in studying the resonance fluorescence from atomic thallium it has been possible to measure the free atomic lifetime, radiation trapping (coherent narrowing), the resonance collision cross sections caused by rare gas thallium collisions. Also in these studies there is evidence of multiple collisions in the excited state-ground state atoms.
Interests
There is a great interest in understanding processes occurring in the ground and excited states of both atoms and molecules. Professor Baird's research in chemical physics involves studies of energy and state transfer collisions, as well as measurement of energy level separations, in simple molecular and atomic species. For example, in studying the resonance fluorescence from atomic thallium it has been possible to measure the free atomic lifetime, radiation trapping (coherent narrowing), the resonance collision cross sections caused by rare gas thallium collisions. Also in these studies there is evidence of multiple collisions in the excited state-ground state atoms. Of interest too are experiments testing the fundamentals of atomic and molecular physics. Research on atomic hydrogen a few years ago played a role in determining the viability of quantum electrodynamics as a correct theory for the electromagnetic interaction to distances on the order of 1013 cm. Current interest is with studies of spin polarized hydrogen at low temperatures. Theoretical work on this system includes studies of collisions at very low energies, calculation of the spin-exchange cross section, nuclear spin relaxation times, and modeling of two dimensional scattering and spin-exchange scattering. Research work on molecular species has involved experimental measurements of fine and hyperfine structure, and theoretical studies of the spin-orbit and spin-dipolar interactions in molecules. Of current interest are efforts to excite molecules to energy levels just below and above the dissociation limit, and to theoretically calculate their positions. The experimental techniques used include optical pumping, coherent excitation, and radio frequencies, as well as digital data handling methods.
Funded Research
N/A
