Resonance laser-induced

The focus of this chapter has been on the synthesis of new catalysts by parallel and combinatorial methods. Another aspect important to the development of new catalysts by these methods is the screening of these large libraries. We will not attempt to cover this topic comprehensively but do feel it is necessary to summarize some of the approaches that have been taken. Methods for screening libraries can be divided into both serial and parallel methods. Generally, the serial methods are adaptations of standard methods that allow for rapid individual analysis of each member of a library. Serial approaches for the analysis of libraries can be as simple as use of an auto sampler on a GC or HPLC system or as advanced as laser-induced resonance-enhanced multiphoton ionization of reaction products above the head-space of a catalyst (16) or microprobe sampling MS (63). The determination of en-antioselectivity in catalysis is a particular problem. Reetz et al. (64) reported the use of pseudoenantiomers and MS in the screening of enantioselective catalysis while Finn and co-workers (65) used diastereoselective derivatization followed by MS to measure ee. 

Morita, N., Kumakura, M., Yamazaki, T., Widmann, E., Masuda, H., Sugai, I., Hayano, R.S., Maas, F.E., Torii, H.A., Hartmann, F.J., Daniel, H., von Egidy, T., Ketzer, B., Muller, W., Schmidt, W., Horvath, D. and Eades, J. (1994). First observation of laser-induced resonant annihilation in metastable antiprotonic helium atoms. Phys. Rev. Lett. 72 1180-1183. 

Emission spectra of anthraquinone radical anions,354 p-xylene-type free radicals,355 and of aromatic hydrocarbon mono- and di-negative ions 356 have been recorded. Fluorescence spectra of a charge-transfer complex have been presented.357 A method using single-mode laser-induced resonance fluorescence to obtain the rotational structure of large molecules has been outlined.358... 

The powerful technique of two-photon absorption, which permits limitations of Doppler broadening to be overcome (see Chapter 1), has been used in a study on sodium atoms in which the Stark effect in the 5s 2Si and 4d D and D levels was observed.188 The radiative lifetimes of the S and D Rydberg levels of Na,189 the use of laser-induced resonance fluorescence for the measurement of small concentrations of Na vapour,170 the quenching of Na(32P) and K(42P) by N2, 02, H2, and HaO,171 the chemi-ionization reactions of photoexcited atoms,172 and excitation of the K(42P ) level in collisions with rare-gas atoms173 have been the subjects of recent reports. 

Dressed molecule picture and laser-induced resonances 61... 

Hamiltonian in an extended space, the direct product of the usual molecular Hilbert space, and the space of periodic functions of f e [0,T]. This extension of the Hilbert space can be made somewhat more transparent by introducing a new time-like variable, to be distinguished from the actual time variable t. This new time variable can be defined through the arbitrary phase of the continuous (periodic) field, as done in Ref. [28, 29]. A variant of the idea is found in the (f, t ) method developed by Peskin and Moiseyev [30] and applied to the photodissociation of HJ [31, 32]. We will continue with the more traditional and simpler formulation of Floquet theory here, as this is sufficient to bring out ideas of laser-induced resonances in the dressed molecule picture. 

S.M. Barnett, A.M. Lane, Increase of mesomolecular formation by laser-induced resonances, J. Phys. B 21 (1988) L523. 

S. Cavalieri, F.S. Pavone, M. Matera, Observation of a laser-induced resonance in the photoionization spectrum of sodium, Phys. Rev. Lett. 67 (1991) 3673. 

R. Buffa, Laser-induced resonances in ionizing radiative collisions. Opt. Commun. 128 (1996) 30. 

FIGURE 2.8 An individual trapped barium ion ( Ba ). Diffraction-limited image of its laser-induced resonance scattering. False-colour display of scattered intensity. A second ion placed 3 pm apart would show up in the lower right part of the figure, but was temporarily excited into its dark metastable state Ds/2. For a colour reproduction of this figure see the colour plate section, near the end of this book. 

The complexes were formed in a supersonic expansion, ionized by a laser induced resonant two-photon ionization process and mass selectively detected in a time-of-flight mass spectrometer. The spectra (Fig. 1) were... 

Zimmermann R, Lenoir D, Kettrup A, Nagel H and Boesl U (1996) On-line emission control of combustion processes by laser-induced resonance-enhanced multiphoton ionization mass spectrometry. Twenty Sixth Symposium (International) on Combustion, pp 2859-2868 Pittsburgh The Combustion Institute. 

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