Anisotropic ESR spectra

Fig. 4.7 Anisotropic ESR spectra of monovalent copper complex in frozen toluene solution, (a) 2 mm band ESR (140 GHz), (b) 3 cm band ESR (9.6 GHz) experimental spectnim, (b ) simulated spectrum with g = (2.0078, 2.0059, 1.9991), A(P ) = (20, 23, 20) G, A(P) = (8, 11, 8) G, and A(Cu) = (20, 0, 17) G for the principal values of the g-tensor and hyperfine coupling tensors of two inequivalent phosphorous and one Cu atom. The spectra are adapted from [R.R. Rakhimov et al. Chem. Phys. Letters 255, 156 (1996)] with permission from Elsevier...

A spin label such as l(m,n), as indicated in Fig. 8.14 is used for the determination of the degree of orientation. The so called order parameter can be estimated by the anisotropic ESR spectra of spin label 1(13,2) in an oriented sample of smectic liquid crystal, as shown in Fig. 8.15 [19]. There is a dramatic difference in the hyperfine splitting and position of the spectrum, when the axis of the long chains is oriented parallel and perpendicular to the direction of the applied magnetic field. 

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