We are trying to simulate solid state 13C NMR using CASTEP followed by MagRes using the following steps. But we are missing correlation between experimental and simulated chemical shift values:
Please let us know if we are missing any important steps.
1. Crystal structure was geometrically optimized by opting NMR shielding and EFG.
2. The generated MagRes file was viewed in the corresponding website for the simulated.
a. We noticed that MagRes is reading the crystal structure always in P1 space group.
3. To correlate experimental Vs Simulated values, we have used the following equation
δiso(sample) = σcalc(ref) – σcalc(sample)
4. Can you please let us know how to get σcalc(ref) from MagRes
a. Please suggest best reference for carbon atoms associated with various functional groups.
5. Is σcalc(sample) is one of three calculated tensors or average of three calculated tensors or is it what we are visually see in the simulated spectra in the MagRes
You need to compute the reference shift yourself, so that you benefit from cancellation of errors -- remember to use the same cut-off energy and pseudopotentials for each calculation.
I recommend you look at the tutorials on the CCP for NMR Crystallography and CASTEP websites for more details and step-by-step instructions:
https://www.ccpnc.ac.uk/docs
http://www.castep.org/CASTEP/OnlineTutorials
All the best,
Phil Hasnip
(CASTEP developer)
Thank you Philip Hasnip. Your answer is helpful. I will get back up to you if get any issues while computing.
- Badges
- Science topic
- Similar topics
- Engineering
- Electrical Engineering
- Electrodes