Dnp freq scan.m

From Spinach Documentation Wiki
Jump to: navigation, search

Microwave frequency scan steady-state DNP experiment.


Returns the steady-state population of the user-specified state as a function of microwave frequency.



This function should normally be called via powder.m or crystal.m wrapper.


    parameters.mw_pwr      -   microwave power, Hz

    parameters.mw_frq      -   row vector of microwave frequencies, rad/s

    parameters.rho_eq      -   thermal equilibrium state

    parameters.coil        -   detection state vector or a horizon-
                               tal stack thereof

    parameters.mw_oper     -   microwave irradiation operator

    parameters.ez_oper     -   Lz operator on the electrons

    parameters.method      -   'backslash' to use Matlab's
                               linear equation solver, 'gmres'
                               to use ILU preconditioned GMRES

    H                      -   Hamiltonian commutation superoperator

    R                      -   unthermalised relaxation superoperator 

    K                      -   chemical kinetics superoperator


    answer                 -   the projection of the equilibrium density matrix 
                               on the user-specified state as a function of the
                               microwave frequency


A simple TOTAPOL based Cross Effect DNP system, set to reproduce Figure 2b from (examples/dnp_solids/cross_effect_freq_scan_3.m);

Dnp example 3.png

Intensity differences are due to a different relaxation model and minor inconsistencies between the stated geometry and the interaction amplitudes used in the original paper.


  1. The relaxation superoperator supplied to this function should NOT be thermalized.
  2. Backslash method is recommended for small spin systems and GMRES method for large ones.
  3. This function can be made to run on GPUs. If you would like that functionality added, send an email to Ilya Kuprov.

See also


Revision 3284, authors: Ilya Kuprov, Walter Kockenberger, Alexander Karabanov