Kpcs.m

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Computes pseudocontact shifts using the PDE method. Computes the three-dimensional distribution of pseudocontact shift field by solving Kuprov-Charnock equation for PCS. For further information on the equations and algorithms used in this function see http://dx.doi.org/10.1039/C4CP03106G

Syntax

    [pcs_vals,pcs_cube]=kpcs(probden,chi,ranges,nxyz,method)

Arguments

    probden - paramagnetic centre probability density cube.

    chi     - electron magnetic susceptibility tensor in cubic Angstroms.

    ranges  - Cartesian axis extents for the electron spin density cube
              as [xmin xmax ymin ymax zmin zmax] in angstroms.

    nxyz    - nuclear coordinates as [x y z] with multiple rows) at which
              PCS is to be evaluated, in Angstroms.

    method  - 'fft' for Fourier transfrom solver (recommended), 'fdiff'
              for a finite difference solver.

Returns

    pcs_vals - pseudocontact shift in ppm at each nucleus.

    pcs_cube - pseudocontact shift field on the same grid as the spin 
               density supplied.

Examples

See the pseudocontact shift analysis tutorial and the examples in nmr_paramag directory of the standard example set supplied with Spinach.

Notes

  1. Minimal three-point schemes are used for the finite difference operators. Increase stencil size in the source code if you have enough memory.
  2. Beware of the periodic boundary condition effects - leave enough space on all sides of your paramagnetic centre probability density for the wraparound PCS to become negligible.

See also

ppcs.m, ipcs.m, ippcs.m, ilpcs.m, lpcs.m, pms2chi.m, pcs2chi.m


Version 1.9, authors: Elizaveta Suturina, Gareth Charnock, Ilya Kuprov