Dual bilinear rotations

Abstract. Bilinear rotations imply differing rotations on a spin I depending on the presence or absence of a bilinear coupling Hamiltonian in connection to a heteronucleus S. As such, spin system selective inversions using BIRD elements, excitations using TANGO, or general (effective) rotations using BANGO and/or BIG-BIRD, as well as multiplicity-edited rotations, are achievable. So far, the well-defined rotations were only imposed on a single spin, e.g., I, while the coupled heteronucleus experienced only an inversion or no rotation at all. Here, we introduce dual bilinear rotations that simultaneously allow spin system selective manipulations on both spins I and S as compared to the coupled spin system IS. Particularly with the advent of multi-receive experiments and/or super-sequences with the necessity of exciting and storing specific spin systems in a flexible way, this may open new possibilities in pulse sequence design. A general derivation of the approach is given, and a quadruple-J-resolved-type experiment for obtaining fully decoupled spectra optimized for different spin systems is introduced for demonstration.