# pms2chi.m

Runs a least squares fitting procedure on top of Equation 10 from http://dx.doi.org/10.1039/c4cp03106g to extract the susceptibility tensor from DFT hyperfine coupling tensors and experimentally observed paramagnetic (contact + pseudocontact) shifts.

## Syntax

    chi=pms2chi(hfcs,shifts,isotopes,nel)


## Arguments

       hfcs   - cell array of 3x3 hyperfine coupling tensors
in Gauss

shifts   - vector of the observed pseudocontact shifts,
excluding the diamagnetic contribution

isotopes   - cell array of character strings specifying
isotopes that exhibit each of the chemical
shifts supplied, for example {'1H','13C'}

nel   - number of unpaired electrons involved


## Outputs

        chi   - the fitted magnetic susceptibility tensor,
cubic Angstroms

err   - least squares error


## Examples

See the paramagnetic shift getting started guide.

## Notes

Gauss units are used for hyperfine couplings because they do not depend on the electron g-tensor.