Overtone a.m

Overtone signal acquisition experiment inthe frequency domain. Syntax:

          spectrum=overtone_a(spin_system,parameters,H,R,K)

where H is the hamiltonian commutation superoperator, R is the relaxation superoperator and K is the chemical kinetics superoperator. The following parameters are required:

   parameters.sweep           vector with two elements giving
                              the spectrum frequency extents
                              in Hz around the overtone frequency

   parameters.npoints         number of points in the spectrum

   parameters.rho0            initial state

   parameters.coil            detection state

Relaxation must be present in the system dynamics, or the matrix inversion operation below would fail to converge. The relaxation matrix should *not* be thermalized.