Femtosecond transient absorption

Tamai, N., Asahi, T, and Masnhara, H. 1993. Femtosecond transient absorption microscope combined with optical trapping technique. Rev. Sci. Instrum. 64 2496. 

Fig. 1. Top Reference spectra for femtosecond transient absorption measurements S-S abs. in solution (thin solid lines), oxidized dye (dye+) abs. in solution (thick solid line), fluorescence for solution (dotted line), steady-state absorption ofNKX-2311/ZnO (dotted-dashed line), and absorption of electrons in the conduction band (dashed line). Bottom Transient absorption spectra of NKX-23ll/ZnO in the spectral range between 600 and 1350 nm at the 2 (thick solid line), 10 (dotted line), 100 ps (thin solid line) delay times after excitation at 540 nm by the femtosecond pulse with the intensity of about 10 pJ.

Perylene bisimide-dithienothiophene derivatives have been prepared (09JPC(A)5039). A femtosecond transient absorption study showed the presence of two positive bands at 490 nm (perylene cation radical) and at 730 nm (perylene anion radical). 

S, Pullen, L. A WalkerII,B. Donovan, and R. J. Sension,Cbem. Phys. Lett.,242,415 (1995). Femtosecond Transient Absorption Study of the Ring-Opening Reaction of 1,3-Cyclohexadiene. 

All systems were probed in steady-state fluorescence, absorption and time resolved emission lifetime studies at room temperature. Additionally, time resolved femtosecond transient absorption and nanosecond laser flash photolysis measurements were carried out. 

The femtosecond transient absorption studies were performed with 387 nm laser pulses (1 khz, 150 fs pulse width) from an amplified Ti Sapphire laser system (Model CPA 2101, Clark-MXR Inc). A NOPA optical parametric converter was used to generate ultrashort tunable visible pulses from the pump pulses. The apparatus is referred to as a two-beam setup, where the pump pulse is used as excitation source for transient species and the delay of the probe pulse is exactly controlled by an optical delay rail. As probe (white light continuum), a small fraction of pulses stemming from the CPA laser system was focused by a 50 mm lens into a 2-mm thick sapphire disc. A schematic representation of the setup is given below in Fig. 7.2. 2.0 mm quartz cuvettes were used for all measurements. 

Fig. 7.2 Two-beam experimental setup for femtosecond transient absorption studies using a white light continuum. A commercially available CPA 2101 laser system delivers the pulses. Ultrashort tunable visible pulses are obtained by the NOPA optical parametric converter. A chopper wheel is used to cut every second pump pulse in order to compare the signal with and without the pump. The white light continuum is generated by a sapphire disc. The time delay between the pump and probe pulses is adjusted by the optical delay rail...

Nanosecond laser Flash Photolysis experiments were performed with 355 and 532 nm laser pulses from a Brilland-Quantel Nd YAG system (5 ns pulse width) in a front face (VIS) and side face (NIR) geometry using a pulsed 450 W XBO lamp as white light source. Similarly to the femtosecond transient absorption setup, a two beam arrangement was used. However, the pump and probe pulses were generated separately, namely the pump pulse stemming from the Nd YAG laser and the probe from the XBO lamp. A schematic representation of the setup is given below in Fig. 7.3. 0.5 cm quartz cuvettes were used for all measurements. 

Ma, C., Du, Y., Kwok, W.M. and Phillips, D.L. (2007) Femtosecond transient absorption and nanosecond time-resolved resonance Raman study of the solvent-dependent photo-deprotection reaction of... 

Thomsen CL, Madsen D, Keiding SR, Thogersen J, Christiansen O. (1999) Two-photon dissociation and ionization of liquid water studied by femtosecond transient absorption spectroscopy./Chem Phys 110 3453-3462. 

Time resolved hole burning spectra were measured by means of a femtosecond transient absorption spectrometer system. A second harmonics of a mode locked cw Nd + YAG laser (Quantronix, 82MHz) was used for a pumping source. A synchronously pumped rhodamine 6G dye laser with a saturable absorber dye jet (DODCl/DQOCI) and dispersion compensating prisms in the cavity was used. The output of the dye laser (lOOfs fwhm, 600pJ/pulse) was... 

Link, S. El-Sayed, M. A. Schaaff, T. G. Whetten, R. L. Transition from nanoparticle to molecular behavior a femtosecond transient absorption study of a size-selected 28-atom gold cluster. Chem. Phys. Lett. 2002, 356, 240-246. 

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