What can short-pulse pump-probe spectroscopy tell us about Franck-Condon dynamics?

Two different pump-probe (PP) setups were developed successfully with different femtosecond pulse lasers. Using a PP setup with an ultra-short pulse laser, the excitation of coherent phonons in GaAs was measured for a calibration and an accuracy test of the developed setup. The frequencies of the coherent phonon modes were in good agreement with reported values [1, 2]. The setups for ZnSe and GaAs were transmission and reflection–type, respectively. When using the ultra-short pulse laser, the signal in the PP experiment was measured by a balanced photo diode.In the other PP experimental setup, built to measure the transient transmittance of bulk ZnSe, the light source and detector differed from the previous PP setup. A strong pulse laser was successfully used for the spectrally resolved pump probe experimental setup. A broadband, high-resolution spectrometer (HR4000CG-UV-NIR) was used as the detector.

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Ultrafast Electron/Energy Transfer and Intersystem Crossing Mechanisms in BODIPY-Porphyrin Compounds

Processes ◽

10.3390/pr9020312 ◽

2021 ◽

Vol 9 (2) ◽

pp. 312

Author(s):

Yusuf Tutel ◽

Gökhan Sevinç ◽

Betül Küçüköz ◽

Elif Akhuseyin Yildiz ◽

Ahmet Karatay ◽

...

Keyword(s):

Energy Transfer ◽

Fluorescence Spectra ◽

Visible Region ◽

Energy Transfer Mechanism ◽

Free Base ◽

Pump Probe ◽

Harvesting Efficiency ◽

Probe Spectroscopy ◽

Absorption Features ◽

Transfer Mechanisms

Meso-substituted borondipyrromethene (BODIPY)-porphyrin compounds that include free base porphyrin with two different numbers of BODIPY groups (BDP-TTP and 3BDP-TTP) were designed and synthesized to analyze intramolecular energy transfer mechanisms of meso-substituted BODIPY-porphyrin dyads and the effect of the different numbers of BODIPY groups connected to free-base porphyrin on the energy transfer mechanism. Absorption spectra of BODIPY-porphyrin conjugates showed wide absorption features in the visible region, and that is highly valuable to increase light-harvesting efficiency. Fluorescence spectra of the studied compounds proved that BODIPY emission intensity decreased upon the photoexcitation of the BODIPY core, due to the energy transfer from BODIPY unit to porphyrin. In addition, ultrafast pump-probe spectroscopy measurements indicated that the energy transfer of the 3BDP-TTP compound (about 3 ps) is faster than the BDP-TTP compound (about 22 ps). Since the BODIPY core directly binds to the porphyrin unit, rapid energy transfer was seen for both compounds. Thus, the energy transfer rate increased with an increasing number of BODIPY moiety connected to free-base porphyrin.

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Classical theory of ultrafast pump-probe spectroscopy: Applications to I2 photodissociation in Ar solution

Journal of Molecular Liquids ◽

10.1016/0167-7322(94)00758-6 ◽

1994 ◽

Vol 61 (1-3) ◽

pp. 153-165 ◽

Cited By ~ 12

Author(s):

Robert M. Whitnell ◽

Kent R. Wilson ◽

YiJing Yan ◽

Ahmed H. Zewail

Keyword(s):

Classical Theory ◽

Pump Probe ◽

Probe Spectroscopy

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