Intrinsic splitting width

At —70.6°C, the exchange rate k and populations Pj and Pj related to the proton tautomerism were obtained. The intrinsic splitting width Av" was then calculated by using the equilibrium constant Kj- and the chemical shift difference Au (Hz) at —70.6°C, a temperature at which the prototropic tautomerism is still fast on the NMR timescale [12]. 

Fig. 11. (Upper) Splitting of pHe+ states due to magnetic interactions, and observable laser transitions between the F+ and F states according to Bakalov and Korobov [33]. (Lower) Observed hyperfine splitting of the unfavoured laser transition (n, L) = (38,34) —> (37, 35) [16]. The laser bandwidth is 1.2 GHz. The solid line is the result of a fit of two Voigt functions (a Gaussian fixed to the laser bandwidth convoluted with a Lorentzian to describe the intrinsic line width) to the spectrum. The intrinsic width of each lines was found to 0.4 0.1 GHz. From Widmann et al. [16]...

As has been made clear, crystal field splittings are not an important aspect of f electron systems. In solution and the solid the intrinsic half-widths of the bands observed in the f f spectra are typically 50 cm and the crystal field splittings seem much the same, so that there is little information on crystal fields to be gained from f - f spectra. Nonetheless, there is clear evidence that crystal field effects do play a role, albeit not a dominant role—and not a well-understood one either. 

In marked contrast, the bridgehead deuteriated cation [154] did not show any sizeable isotope splittings, except small temperature-independent intrinsic isotope shifts. The broadest peak, i.e. the averaged C1/C4 peak, has a line width of 42 Hz at - 122"C, which gives a calculated maximum for K of 1.03 per D at — 122 C. The absence of equilibrium isotope splittings in [154] was confirmed by the H nmr spectrum, which is virtually identical with that of the unlabelled cation [152] except that the peak for the bridgehead protons has only half the intensity. 

No splittings appear in the spectra of the methylene-deuteriated cations [158] and only small temperature-independent intrinsic isotope shifts are observed in the C nmr spectrum. The kinetically broadened signal of the averaged methyl groups in D2-[158] has a line width of 118 Hz at — I30°C which gives a calculated maximum for K of 1.06 per D. The proton spectra are identical with the spectra of the unlabelled cation [97] except for the reduced intensity of the partially deuteriated methylene groups. 

The fast-motional nitroxide ESR spectrum is a superposition of three Lorentzian lines of different widths and, consequently, with different amplitudes when recorded as first derivative of the absorption. Intrinsic first-derivative peak-to-peak widths of fines, A/fpp, of the three components of the nitrogen hyperfine splitting in the fast-motional nitroxide spectra can be expressed as... 

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