The effects of NH3 free rotation on the inelastic neutron scattering spectrum of Ni(NH3)2Ni(CN)4·2C6D6 at 20 K

The vibrational spectra of Ni(NH 3 ) 2 Ni(CN) 4 ·2C 6 D 6 are consistent with distorted NH 3 groups despite the presence of quantum free rotation of these groups even at 1.8 K. The calculated INS vibrational spectrum of an isolated NH 3 NiNH 3 unit is in good agreement with the observed spectrum and reveals a pronounced anisotropic effect of the Debye-Waller factor due to NH 3 rotations. Possible origins of the splitting of the molecular E-modes of the NH 3 groups are investigated and it is probable that the effective symmetry of the local environment is Cs. There is evidence of vibrational/rotational transitions.