Doublerot.m

From Spinach Documentation Wiki
Jump to: navigation, search

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

  answer=doublerot(spin_system,pulse_sequence,parameters,assumptions)

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_outer - outer rotor spinning rate in Hz
  parameters.rate_inner - inner rotor spinning rate in Hz
  parameters.axis_outer - spinning axis of the outer rotor,
                          given as a normalized 3-element
                          vector
  parameters.axis_inner - spinning axis of the inner rotor,
                          given as a normalized 3-element
                          vector
  parameters.rank_outer - 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) for the
                          outer rotor
  parameters.rank_inner - 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) for the
                          inner rotor
  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

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 average of whatever it is that the pulse sequence returns.

Note: arbitrary order rotating frame transformation is supported, inc- luding infinite order. See the header of rotframe.m for further information.

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