Rotor stack.m

Returns a rotor stack of Liouvillians or Hamiltonians. The stack is needed for the traditional style calculation of MAS dynamics.

Syntax

    L=rotor_stack(spin_system,parameters,assumptions)


Arguments

  parameters.axis     - spinning axis, given as a normalized
3-element vector

parameters.offset   - a cell array giving transmitter off-
sets in Hz on each of the spins listed
in parameters.spins array

parameters.spins    - a cell array giving the spins that
the offsets refer to, e.g. {'1H','13C'}

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.orientation - the orientation of the spin system
at rotor phase zero, a vector of

parameters.masframe    - the frame in which the rotations
are applied. The possibilities are:

'magnet' - the initial orientation in the lab frame
(three-angle powder grids will be required)

'rotor'  - the initial orientation in the rotor frame
(two-angle powder grids will be required)

assumptions       - assumption set to be used in generating the
Hamiltonian, see assume.m


Outputs

      L   - a cell array of Hamiltonian or Liouvillian matrices,
one for each tick of the rotor.

rotor_phases - rotor phases at each tick, radians


Notes

Relaxation and kinetics are not included.