# masdnp.m

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Magic angle spinning DNP simulation, returning the rotor period averaged steady state magnetization. This function takes a lot of inspiration from the code donated by Fred Mentink, please cite Fred's papers if you are using it.

## Syntax

    dnp=masdnp(spin_system,parameters)


## Arguments

    parameters.spins     -  the spins to microwave

parameters.rate      -  spinning rate, Hz

parameters.axis      -  spinning axis direction vector.

parameters.max_rank  -  rotor discretization grid rank

parameters.mw_pwr    -  microwave power, rad/s

parameters.mw_frq    -  microwave frequency, Hz

parameters.mw_time   -  microwave irradiation duration
before the average magnetistion
is computed, seconds

parameters.grid      -  the name of the spherical avera-
ging grid

parameters.coil      -  detection state

parameters.verbose   -  set this to 1 to enable diag-
nostic output


## Outputs

    dnp - enhancement of the user-specified state relative to
the thermal equilibrium


## Examples

A detailed walkthough for solid effect and cross effect MAS DNP is given in the example set. For a simple three-spin system discussed in Fred's paper, cross_effect_mas_enlev.m returns the rotor phase dependence of the energy levels in the system:

The energy level population dynamics during the first rotor cycle is returned by cross_effect_mas_dynam.m example:

The energy level population dynamics during the steady state rotor cycle is returned by cross_effect_mas_steady.m example:

and finally the steady state rotor-averaged, powder-averaged DNP amplitude is returned by a call to this function in cross_effect_mas_powder.m example file.

## Notes

1. Increase the rotor rank and the spherical grid size until the answer stops changing. You will likely need huge values for both parameters.
2. This function must be called directly, without a context wrapper.

## See also

Version 2.5, authors: Frederic Mentink-Vigier, Ilya Kuprov