Evidence for magnetic excitations in liquid oxygen

The authors briefly describe the results of a neutron scattering study on the dynamics of liquid oxygen (T=55.0 K,p=2 bar), performed at a temperature just above the melting point. The wavevector dependence of the inelastic intensities shows a pronounced feature of magnetic origin centred at Q=1.2 AA-1 ('zone boundary') reminiscent of those found in the solid beta -phase. These indicate a dynamical antiferromagnetic (AF) interaction in liquid oxygen at a temperature of approximately 2TN (TN approximately=30 K for solid alpha -phase). The AF coupling extends over only a very short range ( approximately=5.2 AA) and an energy scale of between 0.7 and 3 THz.