Nitrogen intensity ratio from

FIG. 23. Variation of the integrated intensity ratio Id/Iq. the maximum position of the G band, rue-and its width Fq against film nitrogen content. (Reproduced from [78].)... 

In the visible between 500 and 650 nni, porphyrins display 4 absorption bands. The intensity ratios between these bands are function of the nature of lateral chains carried by the pyrrolic ring. These bands are the results of electronic transitions of nitrogen atoms of the pyrrolic ring. These transitions occur from the full electronic orbitals of A211 configuration to the empty orbitals of the Eg configuration (Fig. 9.7). 

As stated above, the isotope ratio measurements are made by comparing the ion beam intensities obtained from an unknown sample gas with those from a reference gas. In the case of nitrogen, which in the gaseous form exists as the diatomic molecule N2, and which has only two stable isotopes and N), the isotope ratio measurement is made simply by a comparison of sample and reference ion beams at miz 29 and 28 (i.e., and W N + ). In a... 

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