Raman scattering study of (K$_x$Sr$_{1-x}$)Fe$_2$As$_2$ ($x$ = 0.0, 0.4)
  Polarized Raman spectra of non-superconducting SrFe$_2$As$_2$ and superconducting K$_{0.4}$Sr$_{0.6}$Fe$_2$As$_2$ ($T_c = 37$ K) are reported. All four phonon modes (A$_{1g}$ + B$_{1g}$ + 2E$_g$) allowed by symmetry, are found and identified. Shell model gives reasonable description of the spectra. No detectable anomalies are observed near the tetragonal-to-orthorhombic transition in SrFe$_2$As$_2$ or the superconducting transition in K$_{0.4}$Sr$_{0.6}$Fe$_2$As$_2$. 
A.P. Litvinchuk, V.G. Hadjiev, M.N. Iliev, Bing Lv, A.M. Guloy and   C.W. Chu