AVS 51st International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP15
Electronic Structure of KDP and DKDP Nonlinear Optical Crystals Studied by Soft X-Ray Absorption and Emission Spectroscopies

Tuesday, November 16, 2004, 4:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: S.O. Kucheyev, Lawrence Livermore National Laboratory
Authors: S.O. Kucheyev, Lawrence Livermore National Laboratory
C.F. Bostedt, Lawrence Livermore National Laboratory
T. van Buuren, Lawrence Livermore National Laboratory
T.M. Willey, Lawrence Livermore National Laboratory
S.G. Demos, Lawrence Livermore National Laboratory
T.A. Land, Lawrence Livermore National Laboratory
A.V. Hamza, Lawrence Livermore National Laboratory
T.E. Felter, Lawrence Livermore National Laboratory
L.J. Terminello, Lawrence Livermore National Laboratory
A.J. Nelson, Lawrence Livermore National Laboratory
Correspondent: Click to Email
The surface and bulk electronic structure of KD@sub 2x@H@sub 2(1-x)@PO@sub 4@ single crystals, so-called KDP (x = 0) and DKDP (x > 0), with a deuteration degree x of 0.0, 0.3, and 0.6, is studied by soft x-ray absorption near-edge structure (XANES) and x-ray emission (XES) spectroscopies. High-resolution O K-edge, P L@sub 2,3@-edge, and K L@sub 2,3@-edge XANES and XES spectra reveal that the element-specific partial density of states in the conduction and valence bands is essentially independent of deuteration x. Projected densities of states in the conduction band also appear to be essentially identical for tetragonal and orthorhombic phases, consistent with previous band structure calculations. A decrease in sample temperature from 300 to 77 K results in an ~0.4 eV shift in the valence band edge (probed by XES), with negligible changes to the conduction band edge (probed by XANES) as the material transforms from the tetragonal to orthorhombic phase. We assign XANES and XES peaks based on previous molecular orbital and band-structure calculations. Results also show that high-intensity x-ray irradiation results in material decomposition into water and KPO@sub 3@ cyclo- and polyphosphates.