Isotropic hyperfine coupling experimental/theoretical values

Table 23 Summary of different theoretical data for the isotropic hyperfine couplings of the OH radical (2n state), using the experimental geometry (R=0.970 A). All values are in gauss.

As exhibited by Fig. 10.4, the correlation between theoretical and experimental values of the isotropic hyperfine coupling constants is generally very good. However, the... 

TABLE 10.3 Experimental and Theoretical Values of Isotropic Hyperfine Coupling Constants"... 

It should also be pointed out that the calculation of accurate hyperfine coupling constants is rather difficult. Two factors are involved the isotropic component (Ajso) and the anisotropic component (T,, Tyy, T ). One must have a good description of electron correlation and a well defined basis set in order to calculate accurate isotropic hyperfine couplings. This is not easy to do with molecules the size of the DNA bases. Even when the computational demands are met, the theoretical calculations may deviate more than 20% from the experimental results. Recently it has been shown that the calculation of anisotropic hyperfine couplings for hydrogens are often within 5-10% of the experimental values. The goal is to... 

The theoretical calculations on radical R6 are in good agreement with the experimental results (Table V). The two methylene isotropic hyperfine couplings are-42.9 MHz and 5.1 MHz while the theoretical isotropic couplings are -41.4 and-38.6 MHz. TheC6-H coupling is-28.5 MHz experimentally compared with the theoretical value of -29.9 MHz. The comparison between the experimental and theoretical hyperfine couplings is rated as excellent. 

Theoretical Values of Isotropic and Anisotropic Hyperfine Coupling Constants The theoretical values for the various magnetic nuclei in the azine radials are given in Table 10.3. The correlation of experimental and theoretical values is plotted in Eig. 10.4. The numbering of the protons is given as follows ... 

Figure 8 Correlation of the contact shift predicted theoretically with Eq. (5) with the experimentally measured " Sn isotropic chemical shift vs. (CH3)4Sn] in compounds of composition Ln,Sn207 (Ln = Nd, Pr, La, Sm, Yb, Tm, Eu). Calculations assume a uniform hyperfine coupling constant and use relative values of . (From Ref. 51.)...

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