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 relaxation dynamics are reported of the T1u CO-stretching manifold of W(CO)6 in room temperature n-hexane solution. The frequency and energy content of the tunable 2 ps IR pump pulse strongly influences the distribution of vibrational level population. With broadband transient IR absorption spectroscopy, vibrational T1 lifetimes of the overtone states of W(CO)6 were directly determined to be 140 ± 20 (1σ) ps for ν = 1, 75 ± 20 ps for ν = 2 and 30 ± 15 ps for ν = 3. T1u to Eg intermode energy transfer occurs on the 10–20 ps timescale.