Nitrogen spectrum

M. Holweck, and P. Lindau studied the structure of the nitrogen bands. E. Condon, and R. Mecke discussed the distribution of energy in the band spectrum. M. Duffieux estimated the masses of the particles that produce the nitrogen spectrum. 

FIGURE 36. (a) MIKE spectrum of protonated anisole m/z 109 and (b) CA (nitrogen) spectrum of the m/z 94 ions. Adapted from Reference 452 with permission... 

Figure 3.5 illustrates the increase in resolution that is afforded by increasing the dimensionality of the spectrnm. Neither the one-dimensional proton spectrum nor the one-dimensional nitrogen spectrum shows a large number of resolved peaks. Most of the peaks are overlapped and are difhcult to analyze. However, in the two-dimensional HSQC spectrnm most of the resonances are resolved thus, information can be obtained from virtnally all of the amide groups within the protein. 

The lines within each set correspond to different vibrational states of the ion produced by the ionization. The absorption of a photon with removal of an electron is sufficiently rapid that the nuclei do not have time to move appreciably, as in the Franck-Condon principle. The ionization potential that is determined through photoelectron spectroscopy is referred to as the vertical ionization energy, as represented by a vertical line in a diagram such as that of Figure 23.11. In the nitrogen spectrum it appears that the ionization to the n = 1 vibrational state of the ion is the most probable process for the center set of lines, while in the other two sets the transition to the v = 0 vibrational state is the most probable transition. 

Objective Identify the compounds with the help of their characteristic frequencies and the correlation charts. Spectrum 1-B belongs to a compound which gave a positive Prussian blue precipitate (color test for the presence of nitrogen). Spectrum 19-B belongs to a compound which gave a positive Beilstein test (flame test for chlorine—green). It is an extremely reactive material when in contact with moist air. 

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