fieldsweep.m

Field swept powder EPR spectra. A very rough implementation using expensive eigenfields algorithm, an explicit spherical grid, and a hard-coded Lorentzian line shape function in Fermi Golden Rule.

Syntax

    [spec,parameters]=fieldsweep(spin_system,parameters)

Parameters

    parameters.grid       - initial spherical grid, ideally a non-symmetric
                            one to avoid transition degeneracies; a good
                            start is 'rep_2ang_100pts_sph'

    parameters.spins      - one-element cell array specifying the spin
                            coupled to the microwave field, e.g. {'E'}

    parameters.mw_freq    - microwave frequency, Hz

    parameters.fwhm       - Lorentzian line FWHM, Tesla

    parameters.window     - field sweep window in Tesla, [Bmin Bmax]

    parameters.npoints    - number of points in the sweep

    parameters.tm_tol     - relative transition moment tolerance; 0.01 is
                            a good start

    parameters.rspt_order - perturbation theory order for eigenfields
                            calculation; 2 is a good start, specify Inf
                            for exact diagonalisation

    parameters.int_tol    - powder integration tolerance, balancing speed
                            and integration accuracy

Outputs

    spec              - field-swept EPR spectrum

    parameters.b_axis - magnetic field axis for plotting

Examples

Below is the output of fieldsweep_nitroxide.m file in examples/esr_solids_swept directory.

Notes

Irrespective of the actual sweep extents, the magnetic field in sys.magnet should be set to 1 Tesla. This experiment should be called directly without a context.

See also

rapidscan.m, acquire.m, fieldscan_enlev.m, fieldscan_magn.m

Version 2.5, authors: Ilya Kuprov