Free electron laser experiments

Suzuki, R., Ohdaira, T., Yamada, K., Yamazaki, T. et al. (1996) Slow Positron Study on Dielectric-coated Mirror for Free-Electron-Laser Experiments , J. Radioanalytical Nucl. Chem. 211, 47. 

A. H. Lumpkin, R. B. Feldman, D. W. Feldman, S. A. Apgar, B. E. Carlsten, R. B. Fiorito, D. W. Rule, Optical-transition radiation measurements for the Los Alamos and Boeing free-electron laser experiments, Nucl. Inst. Meth. Phys. Res. A 285 (1989) 343. 

Schematic diagrams of modem experimental apparatus used for IR pump-probe by Payer and co-workers [50] and for IR-Raman experiments by Dlott and co-workers [39] are shown in figure C3.5.3. Ultrafast mid-IR pulse generation by optical parametric amplification (OPA) [71] will not discussed here. Single-colour IR pump-probe or vibrational echo experiments have been perfonned with OP As or free-electron lasers. Free-electron lasers use...

In 1993, the first ultrafast vibrational echo experiments on condensed matter systems were performed using a free electron laser as the source of temporally short, tunable infrared pulses (11). Recently, the development of Ti sapphire laser-based optical parametric amplifier (OPA) systems has made it possible to produce the necessary pulses to perform vibrational echoes using a tabletop experimental system (12,13). The development and application of ultrafast, IR vibrational echoes and other IR coherent pulse sequences are providing a new approach to the study of the mechanical states of molecules in complex molecular systems such as liquids, glasses, and proteins (14-20). While the spin echo, the photon echo, and the vibrational echo are, in many respects, the same type of experiment, the term vibrational echo is used to distinguish IR experiments on vibrations from radio frequency experiments on spins or vis/UV experiments on electronic states. In this chapter, recent vibrational echo experiments on liquids, glasses, and proteins will be described. 

Hill JR, Tokmakoff A, Peterson KA, Sauter B, Zimdars D, Dlott DD, Fayer MD. Vibrational dynamics of carbon monoxide at the active side of myoglobin picosecond infrared free-electron laser pump-probe experiments. J Phys Chem 1994 98 11213-11219. 

An electronic or vibrational excited state has a finite global lifetime and its de-excitation, when it is not metastable, is very fast compared to the standard measurement time conditions. Dedicated lifetime measurements are a part of spectroscopy known as time domain spectroscopy. One of the methods is based on the existence of pulsed lasers that can deliver radiation beams of very short duration and adjustable repetition rates. The frequency of the radiation pulse of these lasers, tuned to the frequency of a discrete transition, as in a free-electron laser (FEL), can be used to determine the lifetime of the excited state of the transition in a pump-probe experiment. In this method, a pump energy pulse produces a transient transmission dip of the sample at the transition frequency due to saturation. The evolution of this dip with time is probed by a low-intensity pulse at the same frequency, as a function of the delay between the pump and probe pulses.1 When the decay is exponential, the slope of the decay of the transmission dip as a function of the delay, plotted in a log-linear scale, provides a value of the lifetime of the excited state. 

The experiments described here were performed on a guided ion beam tandem mass spectrometer [18] that was temporarily installed at the free electron laser facility FELIX (free electron laser for infrared experiments, FOM Institute for Plasma Physics, Nieuwegein, The Netherlands) [19]. A schematic of the experimental setup is shown in Fig. 3.2. Ions are generated in the ion source region (not... 

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