Thread: Order tensor
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Unread 12-28-2005, 08:38 PM
tmc tmc is offline
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Hello,
I have some questions regarding the alignment matrix and I will be very much grateful if you could clarify my doubts.

Question 1:
1) I like to calculate the angle between the magnetic field and X,Y & Z axes of the alignment frame. For that, I have run PALES and got the values for Sxx, Sxy, Sxz, Syy & Syz. From Sxx value I have calculated cos(tx) and cos(ty) from Syy. Substituting these values in 1/2(3cos(tx)*cos(ty)), I calculated Sxy. But, this calculated value does not match with Sxy obtained from PALES.

Question 2:
I found that the saupe parameters are in the order of 10 to the power -3 & above. However, an artile about the implimentation of svd procedure (Losonczi etal., J. Magnetic Resonance, 138,334-342 (1999)) indicates that the value of S's should lie between ~-1.0 to +1.0.

Question 3:
I found in the literature that Dconst= -mu*gamma(i)*gamma(j)*h/8*pi*pi*pi*r*r*r (Zweckstetter & Ad Bax, JACS, 2000, Tsui etal, 2000, J. Bio. Mol. NMR). However, an additional 2/3 term is found in the article by Bastiaan et al., Annual reports on NMR spectroscopy, 1987.
I will be very much thanful if you could help me to understand these.

Thank you
then
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