Phonon Density of States of LaFeAsO1-xFx
  We have 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-principle calculations with the exception of a small difference in Fe mode frequencies. The PDOS reported here is not consistent with conventional electron-phonon mediated superconductivity. 
A.D. Christianson, M.D. Lumsden, O. Delaire, M.B. Stone, D.L.   Abernathy, M.A. McGuire, A.S. Sefat, R. Jin, B.C. Sales, D. ...