# ilpcs.m

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Fits experimental PCS data using the distributed paramagnetic centre model described in http://dx.doi.org/10.1039/c6cp05437d

## Contents

## Syntax

[mxyz,chi,Ilm,pred_pcs,s_mxyz,s_chi,s_Ilm]=ilpcs(nxyz,expt_pcs,ranks,mguess)

## Arguments

nxyz - nuclear coordinates as [x y z] with multiple rows, at which PCS is to be evaluated, in Angstroms. expt_pcs - a column vector of experimental pseudocontact shifts in ppm ranks - row of multipole expansion ranks to be used in the fitting procedure mguess - guess value for the paramagnetic centre position, a three-element vector in Angstrom

## Outputs

mxyz - optimized paramagnetic centre coordinates as [x y z], in Angstroms. chi - optimized magnetic susceptibility tensor in cubic Angstroms. Ilm - {[],[]} cell array of numbers corresponding to the multipole moments defined in the paper cited above: for L=0, Ilm=N/2/sqrt(pi) for L=1, Ilm=[real(I11) I10 imag(I11)] for L=2, Ilm=[real(I22) real(I21) I20 imag(I21) imag(I22)] et cetera. pred_pcs - predicted pseudocontact shift (in ppm) at each of the nuclei. chi - optimized magnetic susceptibility tensor in cubic Angstroms. s_mxyz - standard deviations of paramagnetic centre coordinates as [x y z], in Angstroms. s_chi - standard deviations of magnetic susceptibility tensor elements in cubic Angstroms. s_Ilm - standard deviations of the multipole moments, arranged in the same order as the moments themselves.

## Examples

See the paramagnetic shift getting started guide.

## Notes

- A good initial guess for the paramagnetic centre location is essential for a successful fit.
- Standard derviations are expensive, do not request unless you need them.

## See also

lpcs.m, kpcs.m, ipcs.m, hfc2pcs.m, hfc2pms.m, pcs2chi.m, pms2chi.m

*Version 2.2, authors: Elizaveta Suturina, Ilya Kuprov*