Quadrupolar + CSA + relative angles (CSA->QUAD)

 Example :  Static spectrum with both QUAD & CSA  
 Example :  MAS spectrum with both QUAD & CSA  

The models "int2Q (built in)" or "Quasar (J.P.Amoureux)" both allow computation of spectra in static or finite spinning rates taking into account :

  • the 2nd order quadrupolar interaction
  • the chemical shift anisotropy
  • the orientation of CSA tensor in the Quadupolar tensor

Quadrupolar tensor definition :
  • principal values are sorted |Vyy|<=|Vxx|<=|Vzz| note that Vxx and Vyy have signs opposite to that of Vzz - usually NMR is not sign sensitive for EFG
  • Vzz+Vxx+Vyy=0
  • etaQ is the anisotropy of the Quadrupolar tensor etaQ=Vyy-Vxx/Vzz  with 0<=EtaQ<=1
  • and thus Vxx=1/2 (-EtaQ-1)Vzz  and Vyy=1/2 (EtaQ-1)Vzz

CSA Parameters :
  • principal values are sorted |d33-diso|>|d11-diso|>|d22-diso|
  • diso is the isotropic chemical shift 1/3 (d33+d22+d11)
  • dCS is the axiality of the CSA tensor (d33-diso)
  • etaCS is the anisotropy of the CSA tensor etaCS=(d22-d11)/(d33-diso)
Definitions in agreement with Simpson (Aarhus) M.Bak, J.T.Rasmussen, N.C.Nielsen J. Magn. Reson. 147 296-330 (2000)  

CSA - Quadrupolar angles :

Phi, Chi and Psi orient the CSA tensor in the Quadrupolar tensor principal axes

All definitions of tensors and angles are consistent with that used by Simpson (Aarhus) and by WSolids by K.Eichele (Universität Tübingen)

Static Examples

 Example :  Static spectrum with both QUAD & CSA  
MAS Examples

 Example :  MAS spectrum with both QUAD & CSA