J. Combet et al., PRESSURE-DEPENDENCE OF THE DYNAMICS OF AN ORGANIC INCLUSION COMPOUND INVESTIGATED BY INCOHERENT QUASI-ELASTIC NEUTRON-SCATTERING, Journal of physics. Condensed matter, 9(30), 1997, pp. 403-409
The nitroxide C9H16NO2 (referred to as tano) forms channel inclusion c
ompounds with linear hydrocarbons. At room temperature, both tano and
chain molecules are dynamically disordered. When the temperature is de
creased, one phase transition is observed. The pressure dependence of
the temperature of transition and the evolution of the individual moti
ons have been studied by incoherent quasielastic neutron scattering in
the case of a tano-octane system. The transition temperature increase
s with the pressure with a slope (dT(t)/dP)(P=0) = 24 K kbar(-1). The
transition mechanism is connected to the lock-in of both tano (interco
nversion) and chain (reorientation) molecules, as a result of strong c
orrelations between host and guest substructures. A residual disorder
persists in the low-temperature phase confirming that all the tano mol
ecules are not dynamically equivalent.