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)