High-spectral-brightness coherent XUV radiation has been produced by third-harmonic generation of a transformlimited- bandwidth KrF* laser in gaseous xenon. The observed XUV output, which was continuously tunable from 82.8 to 83.3 nm, had a peak power of 40 mW, a bandwidth <0.01 cm(-1), and absolute frequency control to within 0.04 cm(-1). The utility of this XUV source for high-resolution spectroscopic applications is demonstrated by absorption studies in molecular hydrogen.
A 40-mJ ArF* laser with pulse duration ∼10 ps and spatial and spectral properties close to the transform limits is described. Substantial extraction of the available energy from the final amplifier is demonstrated, a fact providing direct evidence against the presence of significant nonlinear losses in the amplifying medium up to an intensity of ∼1 GW/cm.2
In this paper, we report on the generation of tunable radiation around 79 nm, using frequency mixing of two ArF * photons and a visible dye laser photon. In contrast to harmonic generation with a rather limited tuning range, this method combines the potential of high power excimer lasers (up to 30 W peak powers have recently been measured 1 at the third harmonic of ArF * ) with the broad tunability of dye lasers. The ArF * lasers used in the present experiments is a modified version of a system described previosuly. 2 The output characteristics of the ArF * laser are energy 200 mJ, bandwidth 0.5 cm −1 , pulse duration 7 ns, and wavelength 193.55 nm. The tunable dye laser was operated with stilbene 420, tunable from 416 nm to 458 nm, with an output energy of 5 mJ, bandwidth 0.3 cm −1 , and pulse duration 15 ns. With these lasers, up to 200 mW peak power of mixed radiation have been measured with hydrogen as nonlinear medium. This radiation has a bandwidth of less than 0.8 cm −1 , if gaussian lineshapes are assumed. In order to demonstrate the usefulness of the system as a spectroscopic tool, the source was tuned across the 2 P ½ 9d' autoionizing resonance in argon. Fig. 1 shows the measured absorption profile normalized to the data from Hudson and Carter 3 . The bandwidth of the source can be tested by scanning across the 2 P 3/2 13d states which have an estimated doppler width of 0.22 cm −1
This chapter contains sections titled: Introduction Electron Absorption Spectra of Acyl Halides Photochemical and Radiation-Chemical Formation of Acid Halides Photolysis, Photochemical Oxidation and Reduction of Acyl Halides Photolysis of Acyl Halides in the Presence of Hydrogen Donors, Alkanes and Alkenes Acknowledgment References
