Inelastic-neutron-scattering studies of a quasi-one-dimensional charge-density-wave system: Characterization of interchain interactions

The low-frequency part of the phonon spectrum of perdeuterated-[Pt(en)(2)][Pt(en)(2)I-2](ClO4)(4) (where en = 1,2-diaminoethane) has been measured by inelastic neutron scattering. Longitudinal optical branches quasi-parallel to the acoustic ones are observed along the [xi 00] and [0 xi 0] directions, revealing the existence of a weak coupling of the PtI charge-density-wave chains with their environment. The whole data, obtained in the (a*,b*) reciprocal plane, are well described by a two-dimensional model that allowed the determination of the coupling constant and gaps for thr q=0 wave vector. The linear temperature dependence of the phonon energies indicates an increase in interchain interactions on cooling. [S0163-1829(98)04329-X].