Ultrafast dynamics of the carbonyl stretching vibration in acetic acid in aqueous solution studied by sub-picosecond infrared spectroscopy.
Vibrational energy relaxation of the carbonyl CO stretching modes of CH3COOD and CD3COOD in D2O is studied by frequency-resolved infrared pump-probe spectroscopy. The spectral change caused by the vibrational excitation includes two dynamical components with the time constants of 450 and 980 fs for CH3COOD and 390 and 930 fs for CD3COOD. The two dynamical components exhibit different spectral properties. There are two species of acetic acid forming different complexes with solvent water molecules. The time constants are almost the same for CH3COOD and CD3COOD, suggesting that the vibrational energy deposited to the carbonyl group is first distributed among vibrational modes not related to the methyl group.
Banno
Motohiro
M
Molecular Photoscience Research Center, Kobe University, Graduate School of Science and Technology, Kobe University, Kobe 657-8501, Japan.
Ohta
Kaoru
K
Tominaga
Keisuke
K