We have performed density-functional theory calculations for the V(CO)(6) radical, the CO(Cp)(2) radical, and the CO(Cp)(2)\V(CO)(6) radical pair. Primary interest was in the V(CO)(6) radical in both the isolated species and in the radical pair. Several stable structures were found for the Jahn-Teller-active 17-electron V(CO)(6) radical for both the isolated radical and in the radical pair. We confirmed prior studies that identified a D-3d structure as most stable, a D-4h structure at higher energies, and a transition state of D-2h structure. We also found a new stable structure Of C-2h geometry that is close (similar to130 cm(-1)) to the lowest-energy D-3d structure. We calculated the relative energies of the isolated radical structures and the radical-pair structures as a function of the metal-metal distance. In addition, we estimated interconversion barriers between these structures and found similar results for both the isolated radical and the radical pair. This similarity suggests that the radical pair is rapidly interconverting at room temperature in the same manner as the isolated radical. This has implications in the interpretations of ultrafast electron-transfer dynamics. Specifically, a rise was observed for the radical carbonyl stretch vibration in the radical pair when the ion-pair charge-transfer absorption created excess vibrational energy in the radical pair. The rise time is not likely to be due to rapid geometric interconversion but is probably due to anharmonic coupling between highly excited low-frequency modes and the high-frequency carbonyl stretches leading to a broadened carbonyl absorption band immediately after excitation. The observed rise time in absorption is conjectured to correlate with cooling of the low-frequency vibrations to the solvent over 200 fs.