Interband scattering in MgB2
  The scattering process responsible for connecting the bands remains one of the last open questions on the physical properties of MgB2. Through the analysis of the equilibrium and photo-induced far-infrared properties as well as electron spin resonance of MgB2 we propose a phonon mediated energy transfer process between the bands based on the coupling of quasiparticles to an E2g phonon. 
R.P.S.M. Lobo, M. Elsen, P. Monod, J.J. Tu, Eun-Mi Choi, Hyeong-Jin   Kim, W. N. Kang, Sung-Ik Lee, R.J. Cava, and G.L. Carr