  We report the experimental results of temperature dependent polarized As
K-edge extended x-ray absorption fine structure (EXAFS) of LaFe1-xCoxAsO (x=0.0
and 0.11) single-crystals. By aligning the Fe-As bond direction in the
direction of the x-ray beam polarization we have been able to identify an
anomaly in the Fe-As bond correlations at the tetragonal to orthorhombic
transition at 150K, while previous investigations with standard unpolarized
EXAFS of undoped LaFeAsO powder samples were not able to detect any such
anomaly. Using our approach we have been able to identify in the
superconducting doped sample, LaFe0.89Co0.11AsO, a broad anomaly around 60 K.
The low temperature anomaly has good correlations with the temperature
dependence of several properties like resistivity, magnetic susceptibility,
linear thermal expansion, etc indicating the emergence of the dynamical
oscillations of the Fe - As pairs
