From Spinach Documentation Wiki
Jump to: navigation, search

Fokker-Planck magic angle spinning context. Generates a Liouvillian superoperator and passes it on to the pulse sequence function, which should be supplied as a handle. Syntax:


where pulse sequence is a function handle to one of the pulse sequences located in the experiments directory, assumptions is a string that would be passed to assume.m when the Hamiltonian is built and parameters is a structure with the following subfields:

    parameters.rate     - spinning rate in Hz
    parameters.axis     - spinning axis, given as a normalized
                          3-element vector
    parameters.spins    - a cell array giving the spins that 
                          the pulse sequence involves, e.g. 
    parameters.offset   - a cell array giving transmitter off-
                          sets in Hz on each of the spins listed
                          in parameters.spins array
    parameters.max_rank - maximum harmonic rank to retain in
                          the solution (increase till conver-
                          gence is achieved, approximately
                          equal to the number of spinning si-
                          debands in the spectrum)
    parameters.rframes  - rotating frame specification, e.g.
                          {{'13C',2},{'14N',3}} requests second
                          order rotating frame transformation
                          with respect to carbon-13 and third
                          order rotating frame transformation
                          with respect to nitrogen-14. When
                          this option is used, the assumptions
                          on the respective spins should be
                          laboratory frame.
    parameters.grid     - spherical grid file name. See grids
                          directory in the kernel.

Additional subfields may be required by the pulse sequence. The parameters structure is passed to the pulse sequence with the following additional parameters set:

  parameters.spc_dim  - matrix dimension for the spatial
                        dynamics subspace
  parameters.spn_dim  - matrix dimension for the spin 
                        dynamics subspace

This function returns the powder avrage of whatever it is that the pulse sequence returns.

Note: arbitrary order rotating frame transformation is supported, including infinite order. See rotframe.m for further information.

Note: the state projector assumes a powder -- single crystal MAS is not currently supported.