C–D Modes as structural reporters via dual-frequency 2DIR spectroscopy

Implementation of weak C–D stretching modes as structural reporters via dual-frequency 2DIR spectroscopy is demonstrated. It is experimentally shown that interactions among CD and C≡N modes can provide useful structural constraints. The dephasing times, diagonal and off-diagonal anharmonicities for the CD and CN modes in acetonitrile-d3 are measured. These experiments open an avenue of using deuteration of carbon atoms as a universal labeling strategy for structural measurements via 2DIR spectroscopy.