Infrared phonon activity in pristine graphite
  We study experimentally and theoretically the Fano-shaped phonon peak at 1590 cm$^{-1}$ (0.2 eV) in the in-plane optical conductivity of pristine graphite. We show that the anomalously large spectral weight and the Fano asymmetry of the peak can be qualitatively accounted for by a charged-phonon theory. A crucial role in this context is played by the particle-hole asymmetry of the electronic $\pi$-bands. 
M. Manzardo, E. Cappelluti, E. van Heumen, A. B. Kuzmenko
cond-mat.mtrl-sci