Ph.D., 1979, University of California, Berkeley
Department of Chemistry
Louisiana State University
Baton Rouge, LA 70803
Office: Chopin Hall
Present Research Interests
My research group studies fundamental physical processes of small molecules, and more specifically, we attempt to identify and elucidate theoretically tractable scattering processes that clarify the correlation of electronic and nuclear degrees of freedom. Our primary focus is molecular photoionization, and we examine the vibration and rotation of the ions formed as a function of the photoelectron kinetic energy. Because this requires tunable radiation in the soft x-ray region, we utilize the CAMD (see page 4) synchrotron radiation source. The VUV and x-ray radiation is used to eject electrons from molecular targets. The ions created in excited states can fluoresce, and we determine the deposition of vibrational and rotational energy into the ions from the fluorescence spectra. We characterize phenomena which result in the exchange of vibrational or rotational energy with electronic energy, such as shape resonances and Cooper minima. For example, shape resonances occur when an outgoing electron is temporarily trapped in a quasibound state, and the nature of this state depends strongly on both photoelectron energy and molecular geometry. As a result, our vibrationally resolved investigations of shape resonances provide detailed information on how the photoelectron senses the molecular environment. Similarly, rotational and alignment studies provide information on microscopic aspects of the molecular scattering, providing complementary information to the vibrationally resolved results. Collectively, these investigations illustrate the central theme of our work, namely, that we can develop a deeper understanding of fundamental molecular scattering processes via highly state-resolved experiments.
R.M. Rao, E.D. Poliakoff, K. Wang, and V. McKoy, "Global Franck-Condon Breakdown Resulting from Cooper Minima," Phys. Rev. Lett. 76:2666-69 (1996).
E.D. Poliakoff and R.M. Rao, "Rotational and Vibrational Effects in Photoionization: Bridging the Gap from Microvolts to Kilovolts," J. Electron Spectrosc. Rel. Phenom. 79:361-66 (1996).
E.D. Poliakoff, H.C. Choi, R. Rao, A.G. Mihill, S. Kakar, W. Wang, and V. McKoy, "Photion Rotational Distributions from Near-Threshold to Deep in the Continuum," J. Chem. Phys. 103:1773-87 (1995).
H.C. Choi, R.M. Rao, A.G. Mihill, S. Kakar, E.D. Poliakoff, K. Wang and V. McKoy, "Energy Dependence of Photoion of N2 and CO," Phys. Rev. Lett. 72:44-47 (1994).