  The adiabatic theory of resonance one-phonon Raman scattering in
semiconductor nanocrystals is revised and extended with perturbative
non-adiabatic corrections, given by the Albrecht's B term. This theory is
confronted with the time-dependent perturbation approach, pointing at their
differences and similarities. It is shown that both theories are equivalent in
the limit of weak electron-phonon coupling and non-degenerate or uncoupled
resonant states. Evaluations of the A and B terms for the confined LO phonon in
CdSe and CdS nanocrystals are reported. These evaluations show that the B term
can usually be neglected.
