dnp_freq_scan.m

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Microwave frequency scan steady-state DNP experiment. Returns the steady-state population of the user-specified states as a function of microwave irradiation frequency.

Syntax

    dnp=dnp_freq_scan(spin_system,parameters,H,R,K)

Arguments

   parameters.mw_pwr       -   microwave power, rad/s

   parameters.mw_frq       -   row vector of microwave frequ-
                               ency offsets (rad/s) relative
                               to the reference g-factor

   parameters.g_ref        -   reference g-factor around which
                               frequency offsets are specified

   parameters.rho0         -   thermal equilibrium state

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

   parameters.mw_oper      -   microwave irradiation operator

   parameters.ez_oper      -   Lz operator on the electrons

   H - Hamiltonian matrix, received from context function

   R - relaxation superoperator, received from context function

   K - kinetics superoperator, received from context function

Outputs

   dnp    -  an array of the steady state amplitudes of the
             states specified in parameters.coil as at each
             of the microwave frequencies supplied

Examples

Below is a simple TOTAPOL based Cross Effect DNP example (examples/dnp_solids/cross_effect_freq_scan_3.m), set to reproduce Figure 2b from http://dx.doi.org/10.1016/j.jmr.2011.09.047

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.

Notes

  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.

See also

DNP experiments


Version 2.5, authors: Ilya Kuprov, Walter Kockenberger, Alexander Karabanov, Maria Grazia Concilio