Third spectra

When this analysis was first attempted [9-11] very few values of 1 had been obtained from series limits in the third spectra of the lanthanides, and the first comprehensive sets were calculated from Born-Haber cycles [9]. Subsequent spectroscopic values [12] confirmed the early work and are plotted in Eig. 1.1. In all cases they refer to the ionization process... 

Bi (g). From spectroscopic data, Barratt and Bonar1 obtained, for Bi2 (g) =2 Bi (g), Dz= —18.5. The values for the energy states of gaseous monatomic bismuth are taken from the following first spectra, Thomsen3 and Toshniwal1 second and third spectra, McLennan, McLay, and Crawford.2 See also Bacher and Goudsmit.1... 

SCHEME 12.7 TR ESR study of addition of r of DAR to MMA (Schemes 12.13) in ethyl acetate. Arrows at the spectra point to a signal of substituted benzoyl radical. The top spectrum was obtained under photolysis of DAR only. The second and the third spectra from the top were taken in the presence of MMA. The spectra correspond to adducts of both r s of DAR (predominantly of ketyl radical) to MMA. All radicals are polarized the sign is not shown in the scheme. Vertical arrow points to a signal of a benzoyl radical. ... 

Answer The signal with 8=2 ppm is produced by the protons of the methyl group and the signal at about 7 ppm by the aromatic protons. As the lines have approximately the same width, the ratios of the peak areas are 3 5, 3 2 and 3 1 in the first, second and third spectra, respectively. Hence, the spectra can be assigned as follows 1. Toluene, 2. p-xylene, 3. mesitylene. 

Centers of gravity of 4f 5d above in the third spectra of the lanthanides. 

Racah began his discussion of the second spectra by regretting that the absence of relevant data precluded the construction of formulas of the type represented by eqs. (80)-(82). Instead, he suggested that it might be useful (and much more convenient) to compare differences in energy between the lowest levels of opposite parity (the so-called system differences) in the second and third spectra. He noted, for example, that we can write... 

The characteristic structure of the third and fourth spectra is shown in fig. 1.16. In the third spectra the system A comprises, as before, three groups of configurations. 

The system B degenerates, in the third spectra, into the single configuration... 

Contrary to the situation in the first and second spectra, where the lowest configurations of the A and B systems compete for the title ground configuration, the configuration 4f ( low B ) in the third spectra is lower than 4f (5d + 6s) ( low A ) by such an amount that most of the transitions between... 

Smll and EuIII. The transition from /ij to LS coupling, on approaching the middle of the group from both sides occurs in Pmll 4f ( H)6s and Gdll 4fVF)6s in the second lanthanide spectra and in Smlll 4f H)6s and TbIII 4f ( F)6s in the third spectra. 

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