Dnp freq scan.m

Microwave frequency scan steady-state DNP experiment.

Description

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

Syntax

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


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

Arguments

    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.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


Returns

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


Examples

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

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.
3. This function can be made to run on GPUs. If you would like that functionality added, send an email to Ilya Kuprov.