title: Vibrational dynamics of the CO stretching of 9-fluorenone studied by visible-pump and infrared-probe spectroscopy.
abstract: We studied the effects of hydrogen bonds on the vibrational structures and vibrational dynamics of the CO stretching mode of 9-fluorenone (FL) in the electronically excited state in aprotic and protic solvents using sub-picosecond visible-pump and IR-probe spectroscopy. The transient IR spectrum of the CO stretching band in methanol-d4 has two bands at 1529.9 cm(-1) and 1543.4 cm(-1), which are assigned to an FL-solvent complex and free FL, respectively. In the aprotic solvents, the CO stretching bands show blue-shifts in time. This shift is due to vibrational cooling, which is derived from anharmonic couplings with some low-frequency modes. Interestingly, a red-shift is observed at later delay time for the band at 1529.9 cm(-1) in methanol-d4. A possible mechanism of this spectral shift is related to the hydrogen bond dynamics between the solute and solvent.
authors: Department of Chemistry, Graduate School of Science, Kobe University, Molecular Photoscience Research Center, Kobe University, Nada, Kobe, 657-8501, Japan. tominaga@kobe-u.ac.jp.
authors: Yuki
authors: Y
authors: Fukui
authors: Kaoru
authors: K
authors: Ohta
authors: Keisuke
authors: K
authors: Tominaga
mesh_terms: D004583:Electrons; D005449:Fluorenes / Q000737:chemistry*; D006860:Hydrogen Bonding; D011789:Quantum Theory; D012996:Solutions; D012997:Solvents / Q000737:chemistry*; D013055:Spectrophotometry, Infrared / Q000295:instrumentation / Q000379:methods; D014732:Vibration
chemical_list: D005449:Fluorenes; D012996:Solutions; D012997:Solvents; C028401:9-fluorenone