The typical energy separation between D-like and P-like electronic states in CdSe nanocrystals is
often of similar magnitude to the S-P splitting in the conduction band and would therefore similarly
preclude efficient electron decay via multiple phonon emission. Despite the puzzling observation of
fast D-to-P intraband relaxation, however, little is known about the mechanisms governing it. This
work shows that the same process responsible for fast P-to-S electron decay, namely Auger cooling,
plays a fundamental role to allow fast population of the P state, from higher excited states, in
case of high-energy excitations. Since in nanocrystals the latter are employed to initiate carrier
multiplication, where multiple excitons are created from the absorption of a single photon, the D
electron lifetimes calculated here could provide a reference for the estimate of the carrier multipli-
cation time constant, the magnitude of which is still object of intense debate. These results also
provide a further proof of the suitability of the Auger cooling model to explain electron relaxation
in semiconductor nanocrystals.