Phonon Density of States of LaFeAsO 1-x F x Brent Fultz (Caltech), DMR 0520547

1. Phonon Density of States of LaFeAsO1-xFxBrent Fultz (Caltech),DMR 0520547 Research: We studied the phonon density of states (PDOS) in LaFeAsO1-xFx with inelastic neutron scattering methods. The PDOS of the parent compound (x=0) is very similar to the PDOS of samples optimally doped with fluorine to achieve the maximum Tc (x=0.1). Good agreement is found between the experimental PDOS and first-principles calculations. The PDOS curves are not consistent with conventional electron-phonon mediated superconductivity. All measurements were performed with the newly-operational ARCS spectrometer at the Spallation Neutron Source, built and operated by DOE. All data reduction, and most of the first-principles calculations, were performed with software developed under the DANSE project, funded by the NSF. A.D. Christianson, et. al., submitted to Phys. Rev. Lett. Inelastic neutron scattering intensity S(Q,E) of super-conducting LaFeAsO0.9F0.1 at 10 K. a. Phonon DOS of superconducting (sc) phase at two temperatures. b. Phonon DOS of non-sc and sc phase at one temperature. Little difference is found between the curves.

2. DANSE Diversity and OutreachPaul Butler (NCNR),DMR 0520547 Broader Impacts: As part of its Diversity Strategic Plan, several DANSE subgroups mentored a minority undergraduate student this summer. The SANS sub-group for example sponsored a student from Puerto Rico, Raiza Cortes-Hernandez, through the NIST SURF program. Her project aimed to understand how to provide intelligent guidance on input parameters for the PrView prototype. This prototype has already been successfully used to help understand the deformation of proteins as they pass through a separation medium. This work was just submitted for publication. • Please insert an image or group of images here. Please use lettering that is clearly visible (i.e. not too small). Please include a brief caption. • Use pic of surf student? • Use pic of SliceView • Use title of paper and ack? “[2D] Model functions are courtesy of the DANSE Project.” From “What’s New” in 2008 release of NIST IGOR package “…Furthermore, it has been instrumental in allowing me to obtain unique results which had previously been inaccessible and exceedingly difficult to simulate or analyze when using other software packages…” From Australian X-ray scatterer