Abstract Dynamics of α-glycine from normal, C-deuterated and N-deuterated samples at 20 K has been investigated through high-resolution neutron-scattering experiments in the energy-transfer range 5–250 meV. Torsional peak of NH + 3 is found to be split, an observation made for the first time using neutrons. The torsional potential is seen to be anharmonic. Coupling of other modes to the motion of hydrogen atoms of NH + 3 and CH 2 is discussed.