[1] NIST, Mat Sci & Engn Div, Gaithersburg, MD 20899 USA
[2] Oak Ridge Natl Lab, Natl Inst Computat Sci, POB 2009, Oak Ridge, TN 37831 USA
[3] Univ Tennessee, Joint Inst Computat Sci, Knoxville, TN 37996 USA
[4] NIST, Engn Phys Div, Gaithersburg, MD 20899 USA