Neutron scattering by collective excitations in p-anoxyanisole

In the paper results of coherent inelastic neutron scattering experiments in deuterated p-azoxyanisole (PAA) are reported. The scattering measurements were performed on the triple axis spectrometers at the cold source of the EL3 reactor in Saclay and at the WWRM reactor in Budapest. The incident neutron wavelength was 3 A at EL3 and 2 A at WWRM. All experiments were performed at 125 deg C and in order to orient the molecules, a permanent magnet with an induction of 3.2 KOe in a 30 mm wide air gap was used. The experiments resulted in surprisingly sharp phononlike resonances so one may conclude that nematic PAA oriented in a magnetic field has a more solid-like character than was supposed so far. (Sz.N.Z.)