AVS 52nd International Symposium
    Surface Science Friday Sessions
       Session SS2-FrM

Paper SS2-FrM9
Using Nano-focussed Bremstrahlung Isochromat Spectroscopy (nBIS) to Determine the Unoccupied Electronic Structure of Pu

Friday, November 4, 2005, 11:00 am, Room 203

Session: Electronic Structure of Surfaces
Presenter: J.G. Tobin, Lawrence Livermore National Laboratory
Authors: M.T. Butterfield, Lawrence Livermore National Laboratory
J.G. Tobin, Lawrence Livermore National Laboratory
N.E. Teslich Jr., Lawrence Livermore National Laboratory
R.A. Bliss, Lawrence Livermore National Laboratory
M.A. Wall, Lawrence Livermore National Laboratory
A.K. McMahan, Lawrence Livermore National Laboratory
B.W. Chung, Lawrence Livermore National Laboratory
A.J. Schwartz, Lawrence Livermore National Laboratory
Correspondent: Click to Email
The investigation of the actinides is of great interest because of their unique electronic structure. At the pivotal point of the behavior of the electronic structure of the actinide series is plutonium. Pu has the most complex phase diagram of all metals, both with regard to the intricacy of the crystal structures and the number of different phases. While there are a number of ongoing experimental efforts directed at determining the occupied electronic structure of Pu, there is essentially no experimental data on the unoccupied electronic structure of Pu. We aim to determine the conduction band (unoccupied) electronic structure of Pu and other actinides in a phase specific fashion and emphasizing bulk contributions by using Nano-focussed Bremstrahlung Isochromat Spectroscopy (nBIS). BIS is the high-energy variant of inverse photoelectron spectroscopy (IPES: electron in, photon out), which is essentially the time reversal of photoelectron spectroscopy (photon in, electron out). IPES can be used to follow the dispersion of electronic states in ordered samples. Owing to its low energies, IPES is usually very surface sensitive. However, by working at higher energies, we will sample preferentially for bulk properties, downgrading the impact of surface effects, following a philosophy similar to that of Mo et al.@footnote 1@ Thus, from BIS, we would have a direct measure of the conduction band or unoccupied electronic structure of the bulk Pu. By using a nano-focused electron source associated with a SEM, we hope to gather phase specific information from crystallites within polycrystalline Pu samples. We will discuss the experimental arrangement required to carry out such an experiment and our progress in building such a system. Acknowledgements :This work was performed under the auspices of the U.S. DOE by University of California, Lawrence Livermore National Laboratory under contract W-7405-Eng-48. @FootnoteText@@footnote 1@S.-K. Mo et al, Phys. Rev. Lett. 90, 186403.