  Different energy shifts for majority and minority electrons occur. Thus, for
example in case of (laser) excited ferromagnetic metals majority and minority
electrons may respond differently in time during closing the exchange
splitting. Spin flip transitions of the hot electrons due to electron
interactions cause quasi hybridization of the spin split states. This is also
the case in itinerant ferromagnetic metals due to hopping between sites having
magnetic moments pointing in direction of the magnetization (+) and opposite
direction (-) and with energy levels $\varepsilon^+_{i\sigma}$ and
$\varepsilon^-_{i\sigma}$. For energetic reasons the molecular field acts
asymmetrically on the spins of the electrons and on spin flip transitions and
thus causes different lifetimes of minority and majority electrons and spin
dependent electron energy shifts. Quite general minority hot electrons in spin
split states may respond faster than majority electrons at non--equilibrium.
The molecular field acting on the spins delays spin flip transitions $\uparrow
\rightarrow \downarrow$ and thus a response of the hot majority electrons and
their energy levels. The closing of the exchange splitting in the electron
spectrum of ferromagnetic transition and rare--earth metals, ferromagnetic
semiconductors, spin split quantum well states in thin ferromagnetic films,
etc. will reflect this. The time and spin dependent energy shifts of electrons
at non--equilibrium may cause interesting behavior, in particular of magnetic
tunnel junctions, spin currents etc.. In ferromagnets the moment reversal
lifetime of (local) magnetic moments parallel to the global magnetization is
larger than of moments pointing in opposite direction.
