Surface dynamics of graphite probed by soft x ray linear dichroism in Auger emission yield

Time resolved near edge x ray absorption with Auger electron detection is employed as a surface sensitive probe to study the dynamics of surface atomic motion in graphite upon laser excitation. To this end, ultrafast changes in photoelectron spectra with a focus on carbon KVV Auger intensities are used as probe in a pump probe scheme with pulsed femtosecond near infrared laser excitation of a highly oriented pyrolytic graphite HOPG sample. The dynamics of the HOPG surface excitation at the K edge appears as transient change in Auger yield. Since the directional bond character of carbon is reflected in linear dichroism of x ray absorption, the transient angular variation of the 1s amp; 8594; amp; 960; transitions can be used to uncover the laser induced dynamics of the atomic surface structure which shows a huge anisotropy upon usage of s or p polarized x ray probe pulses, respectivel