pcs_combi_fit.m

Combinatorial PCS fitting function. This function takes into account potential ambiguities in diamagnetic and paramagnetic NMR assignments.

Syntax

[d_shifts,p_shifts,pcs_theo,pcs_expt,chi,total_theo]=pcs_combi_fit(parameters)

Arguments

parameters.hfcs - cell array of 3x3 hyperfine tensors,

                        in Gauss, usually out of gparse() or
                        something similar

    parameters.nel    - number of unpaired electrons involved

    parameters.isotopes - cell array of isotope specificati-
                          ons, e.g. {'1H','1H'}

    parameters.spin_groups - cell array of integer vectors
                             specifying the numbers of spins
                             that have each of the chemical
                             shifts specified, e.g.
                             {[28 22 30]; [25 33 81]}

    parameters.d_shifts - a vector of unique diamagnetic che-
                          mical shifts, in ppm

    parameters.p_shifts - a vector of unique paramagnetic
                          chemical shifts, in ppm

    parameters.d_ambig - a cell array of integer vectors spe-
                         cifying the spins for which the dia-
                         magnetic assignment can potentially
                         be swapped around.

    parameters.p_ambig - a cell array of integer vectors spe-
                         cifying the spins for which the para-
                         magnetic assignment can potentially
                         be swapped around.

Outputs

d_shifts - diamagnetic chemical shifts, optimally permuted

    p_shifts - paramagnetic chemical shifts, optimally permuted

    pcs_theo - theoretical pseudocontact shifts

    pcs_expt - experimental pseudocontact shifts from optimally
               permuted assignments

    chi      - rank 2 part of the magnetic susceptibility tensor,
               in cubic Angstrom

    total_theo - theoretical total NMR chemcial shifts, computed
                 as a sum of d_shifts and pcs_theo

Examples

See combi_fit_1.m and combi_fit_2.m files in examples/nmr_paramag directory.

Notes

Complexity scaling of the combinatorial procedure is very steep - specifying more than seven ambiguous atoms is not a good idea.

See also

ppcs.m, lpcs.m, kpcs.m, ipcs.m

Version 2.1, authors: Ilya Kuprov, Elizaveta Suturina