Dual bilinear rotations

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.