Set the relaxation dispersion spin-lock offset (omega_rf).
spectrum_id: The spectrum ID string to associate the spin-lock offset to.
offset: The spin-lock offset, omega_rf, in ppm.
This sets the spin-lock offset, omega_rf, for the specified R1rho spectrum in ppm.
To set a spin-lock offset of 110.0 ppm for the spectrum `nu1_2.1kHz_relaxT_0.010', type one of:
[numbers=none] relax> relax_disp.spin_lock_offset('nu1_2.1kHz_relaxT_0.010', 110.0)
[numbers=none] relax> relax_disp.spin_lock_offset(spectrum_id='nu1_2.1kHz_relaxT_0.010', offset=110.0)