LURE48 E=6.95 eV

LURE54 E=7 eV

LURE84 E=6.9 eV

LURE84 E=6.9 eV

LURE88 E=7 eV

LURE88 E=7 eV

Fig. 2.12 Variations of the electrical field vector in the (x,y) frame at a fixed z versus time (observer is facing the beam light) as expected at the exit of the synchrotron undulator. The sign of Stokes parameter S3 is displayed in the center of the corresponding figures (other examples and experimental conditions are given in Alcaraz et al. 1999)

The determination of the four Stokes Parameters allows the description of intensity, phase, and polarization of electromagnetic radiation.

2.8 Chromatographic Resolution of Enantiomers

Despite the wide range of applications of chiroptical techniques, the hitherto most powerful tool for qualitative and quantitative identification of chiral analytes of unknown nature is the chromatographic method. This method benefits from a number of great advantages: Chromatography - both gas-liquid as well as liquid-liquid - is able to separate and identify very small amounts of chemicals, in the order of a few nanograms and below; it allows the reliable identification of unknown compounds -especially if it is combined with a mass spectroscopic detection unit. In Analytical Chemistry, the separation of enantiomers is called "resolution" and is widely used to gain information on chiral systems. Today, most analytical laboratories are

Fig. 2.13 Schematic view of elliptical polarized electromagnetic radiation including parameters deducing the four Stokes parameters. The orthogonal coordinate system is formed by r and l, the distances a, a', and b are given with the angles P and y

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