ULTRAFAST INFRARED-SPECTROSCOPY OF VIBRATIONAL CO-STRETCH UP-PUMPING AND RELAXATION DYNAMICS OF W(CO)(6)

The ultrafast infrared (IR) vibrational up-pumping and energy relaxati on dynamics are reported of the T-1st CO-stretching manifold of W(CO)( 6) in room temperature n-hexane solution. The frequency and energy con tent of the tunable 2 ps IR pump pulse strongly influences the distrib ution of vibrational level population. With broadband transient IR abs orption spectroscopy, vibrational T-1 lifetimes of the overtone states of W(CO)(6) were directly determined to be 140 +/- 20 (1 sigma) ps fo r upsilon = 1, 75 +/- 20 ps for upsilon = 2 and 30 +/- 15 ps for upsil on = 3. T-1u to E(g) intermode energy transfer occurs on the 10-20 ps timescale.