The temp. dependence of the absorption and fluorescence spectra of colloidal CdSe nanocrystals was compared for three different shapes (dots, rods, and tetrapods) at 4-300 K. While the shift of the fluorescence max. indicates little dependence on the shape, the broadening of the emission spectrum behaves very differently for dots and rods, indicating major differences in the broadening mechanisms for different shapes. Tetrapods behave more similarly to dots, which suggests that the lowest exciton state is centered at the core. [on SciFinder (R)]