Parabolic-band optical energy sharing ($K_e=(E_{\gamma }-E_g)m_h^{\ast }/(m_e^{\ast }+m_h^{\ast })$)

A vertical direct transition at a common wavevector puts an electron above the conduction edge and leaves a hole below the valence edge. Their parabolic kinetic energies are inversely proportional to their effective masses. The excess photon energy is therefore split as $K_e/K_h=m_h^{\ast }/m_e^{\ast }$, rather than equally unless the masses match. The initial valence electron energy is $-K_h$ relative to its band maximum; the final conduction energy is $E_g+K_e$.