Modern techniques of liquid state physics have been successfully used to probe the microscopic structure and dynamics of a variety of multicomponent liquids in which relative ordering of the species is present near freezing. The alkali halides are prototypes for this specific type of short-range order in relation to the nature of bonding, but the systems in question also include other monovalent and polyvalent metal-ion halides, alkali-based intermetallic compounds and chalcogen-based alloys. A viewpoint is taken in this review which gives attention to the relations between liquid and solid phase properties across melting for compound systems at stoichiometric composition. In addition, large deviations for stoichiometry can be realised in the liquid phase, to display trends of evolution of structure, bonding and electronic states with composition.

https://iopscience.iop.org/article/10.1088/0034-4885/49/9/002/pdf

Structure and dynamics of molten salts

Nuclear Data Sheets for A=132

2H‐nuclear magnetic resonance(NMR)‐spin–lattice relaxation experiments have been performed for studying the crossover from viscous (α process) to secondary (β processes) dynamics in the van der Waals liquid orthoterphenyl and the H‐bridged network glycerol. The essential and general features, observed in both systems, are the following: (a) a dominating α process in the liquid and viscous regime; (b) a change from exponential to nonexponential spin–lattice relaxation as the temperature is lowered below a characteristic temperature above Tg; (c) the existence of a slow (>10−9 s) secondary reorientational process in the highly viscous regime; and (d) the existence of a fast (∼10−12 s) local process in the glassy state. Whereas the slower process is shown to be the one known from dielectric studies, we attribute the fast mode to a β process found in quasielastic neutron scattering.

The molecular dynamics around the glass transition and in the glassy state of molecular organic systems: A 2H−nuclear magnetic resonance study

The partial structure factor SCC(q) of liquid Li0.8Pb0.2 is determined at five different temperatures between the liquidus temperature TL and (TL+230)K. Its temperature dependence can be described as a simple function of a q-space potential. Combining X-ray and neutron diffraction patterns, approximate curves for SCC(q) and SNN(q) are obtained for Li0.5Pb0.5 and Li0.62Pb0.38.

http://iopscience.iop.org/article/10.1088/0305-4608/12/7/005/pdf

Chemical short-range order in liquid LiPb alloys

Observation d'un nouveau mode collectif de haute frequence specifique aux melanges binaires de liquides avec difference importante de masse, dans une simulation par ordinateur de Li 0,8 Pb 0,2 . La vitesse de propagation de ce mode est plus de trois fois plus grande que la vitesse ordinaire du son

Fast sound in two-component liquids.

Dynamics of concentration fluctuations in a heterocoordinated binary liquid alloy

By the method of time differential perturbed angular distribution following a nuclear reaction, the relaxation rateT

 r
 −1
 of the 8 msI
π=10+ isomer of132Xe has been measured in liquid Te. Between 670 °K (supercooled liquid) and 1,000 °K the rate decreases from about 720/s by about a factor of two. From existing experimental material it is concluded thatT

 r
 −1
 is mainly due to quadrupolar interaction (T

 r
 −1
 ≈T
 Q
 −1
 ). Its magnitude is discussed considering the metallic and the noble gas limit as models for the Xe-Te-interactions. The temperature dependenceT
Q(T) apparently does not correlate with the diffusion constant of Te in contrast to a simplified theoretical treatment. — The nuclearg value of the isomer has been determined to be g=(−)0.195(5) thus confirming the configuration (vh11/2)2.

Nuclear spin relaxation of Xe in liquid Te

Dynamical structure factor of concentration fluctuations Scc (Q, ω) measured in the heterocoordinated liquid alloy Li0.8Pb0.2

Mössbauer scattering and neutron scattering on liquid glycerol

A measurement of the quasielastic neutron scattering from liquid 7~i,~b has bgen performed at a time of flight spectrometer (E = 4 . 1 meV, AE = 0.28 meV) for q(E=O) = 0.25 ... 2.5 A-l . Corrections for background, absorpt?on, self shie18ing, and multiple scattering were applied and the spectra were reduced to cross sections by normalization to vanadium. Since the coherent scattering lengths average to zero, the intensity observed is essentially due to the concentr'ation fluctuation structure factor Sm(q,E). Scc(q,E) shows a pronounced quasielastic peak around q 1.5 In the region of the peak, the energy width narrows down by about a factor of two (de Gennes narrowing). A fit in terms of a sum of Lorentzians is attempted which corresponds to an extrapolation of the description valid in the hydrodynamic limit. The self diffusion constant for Li is derived from the 7 ~ i incoherent scattering and an interdiffusion constant from Scc(q,E).

D. Quitmann

Papers

Dynamics of concentration fluctuations in a heterocoordinated binary liquid alloy

Nuclear spin relaxation of Xe in liquid Te

Dynamical structure factor of concentration fluctuations Scc (Q, ω) measured in the heterocoordinated liquid alloy Li0.8Pb0.2

Mössbauer scattering and neutron scattering on liquid glycerol

DYNAMICAL CONCENTRATION FLUCTUATIONS IN LIQUID Li4Pb