Molecular dynamics in DTGS (ND3) by quasielastic and inelastic neutron scattering

The paper presents the last of our QENS and INS measurements on triglycine sulphate DTGS (ND3) at NEAT - BENSC neutron spectrometer. Using an energy window of 0.093 meV we have completed the information obtained in our previous measurements that were carried on non-deuterated TGS. By replacing the protons from amino groups of TGS with deuterons we have been able to observe the dynamical changes in the QENS pattern. The quasielastic line broadening in this case is mainly due to the flip jump diffusion motion of the protons which belong to CH2 group of the GI glycine molecule in DTGS. The residence time associated to this motion is about 4.2 ps. The second part of the paper is devoted to lattice phonons and internal molecular normal modes. The peaks observed in the generalized density of states were compared with optical spectroscopy data. The agreement is good.