Double angle rotation theory

Krivdin and co-workers ° applied a double perturbation theory (DPT) at the second order level of approximation formalism to examine the dihedral angle dependence of the Fermi-contact (FC) contribution to nuclear spin-spin coupling constants. The authors have derived an analytical expression relating the FC term of /(H,H) across the aliphatic single carbon-carbon bond to the dihedral angle describing inner rotation around the C-C bond in the ten-electron ten-orbital moiety H-C-C-H. In particular, the authors have shown that extrema of H,H) are observed at q> = nn [n = 0, 1, 2,...), which provides a theore-... 

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