The imaginary part of the magnetic dipole-dipole cross correlation spectral density in spin 1/2 systems generates a novel type of three-spin Hamiltonian with terms IizIjzIkz, IizIjxIkx and IizIjyIky and permutations in the spin labels i, j, k. These terms cause asymmetric positions of the spin multiplet components, which could not be explained by scalar J-coupling and chemical shift terms.