Ultrafast Time-Resolved Pump鈥揚robe Spectroscopy of PYP by a Sub-8 fs Pulse Laser at 400 nm

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• 作者：Jun Liu ; Atsushi Yabushita ; Seiji Taniguchi ; Haik Chosrowjan ; Yasushi Imamoto ; Keiichi Sueda ; Noriaki Miyanaga ; Takayoshi Kobayashi
• 刊名：The Journal of Physical Chemistry B
• 出版年：2013
• 出版时间：May 2, 2013
• 年：2013
• 卷：117
• 期：17
• 页码：4818-4826
• 全文大小：459K
• 年卷期：v.117,no.17(May 2, 2013)
• ISSN：1520-5207

文摘

Impulsive excitation of molecular vibration is known to induce wave packets in both the ground state and excited state. Here, the ultrafast dynamics of PYP was studied by pump鈥損robe spectroscopy using a sub-8 fs pulse laser at 400 nm. The broadband spectrum of the UV pulse allowed us to detect the pump鈥損robe signal covering 360鈥?40 nm. The dependence of the vibrational phase of the vibrational mode around 1155 cm^鈥? on the probe photon energy was observed for the first time to our knowledge. The vibrational mode coupled to the electronic transition observed in the probe spectral ranges of 2.95鈥?.05 and 3.15鈥?.35 eV was attributed to the wave packets in the ground state and the excited state, respectively. The frequencies in the ground state and excited state were determined to be 1155 卤 1 and 1149 卤 1 cm^鈥?, respectively. The frequency difference is due to change after photoexcitation. This means a reduction of the bond strength associated with 蟺鈥撓€* excitation, which is related to the molecular structure change associated with the primary isomerization process in the photocycle in PYP. Real-time vibrational modes at low frequency around 138, 179, 203, 260, and 317 cm^鈥? were also observed and compared with the Raman spectrum for the assignment of the vibrational wave packet.