Displaying NMR results

A CASTEP NMR calculation computes the chemical shielding tensor and the electric field gradients for all of the atoms in the system.

NMR in CASTEP is part of the separately licensed module NMR CASTEP. NMR calculations can only be performed if you have purchased this module.

NMR properties are dynamic (that is, they are not present on atoms until they are assigned during analysis).

To display the shielding tensor

  1. Choose Modules | CASTEP | Analysis from the menu bar to display the CASTEP Analysis dialog.
  2. Select NMR from the list of properties.
  3. Make sure that the desired 3D Atomistic document is the active document.
  4. Click the Assign isotropic chemical shielding to structure button to import the data into the model.
  5. Right-click in the 3D Viewer and select Label from the shortcut menu. Set the Object type to Atom, select NMRShielding from the Properties list, and click the Apply button to display the shielding tensors.

To display the electric field gradients

  1. Choose Modules | CASTEP | Analysis from the menu bar to display the CASTEP Analysis dialog.
  2. Select NMR from the list of properties.
  3. Make sure that the desired 3D Atomistic document is the active document.
  4. Click the Assign electric field gradients to structure button to import the data into the model.
  5. Right-click in the 3D Viewer and select Label from the shortcut menu. Set the Object type to Atom, select EFGQuadrupolarCoupling or EFGAsymmetry, as appropriate, from the Properties list, and click the Apply button to display the electric field gradients.

To display the J-coupling constants

  1. Choose Modules | CASTEP | Analysis from the menu bar to display the CASTEP Analysis dialog.
  2. Select NMR from the list of properties.
  3. Use Results file selector to pick the right results file; in this case it should be a seedname_NMRJC.castep file.
  4. Click the Show J-coupling constants button to generate and open a study table reporting the calculated J-coupling constants. The study table document will be named seedname_NMRJC JCoupling.std.

    The study table contains two sheets, one with the summary of the results (atom pairs, corresponding interatomic distances, and isotropic and anisotropic components of the J-coupling tensor) and one with the detailed breakdown of contributions to the isotropic coupling (Fermi contact term, spin-dipole term, paramagnetic, and diamagnetic contributions).

  5. Right-click in the 3D Viewer and select Label from the shortcut menu. Set the Object type to Atom, select ServerAtomName from the Properties list, and click the Apply button to display the atom names that are shown in the first two columns of the Summary sheet of the study table.
See Also:

NMR selection - CASTEP Analysis dialog

NMR J couplings