Coherent Dynamics of Liquid Sodium at 423 K

Abstract

Using a self-consistent theoretical method, the coherent dynamics of particles in a coupled liquid of sodium atoms at 423 K have been predicted. The modified microscopic theory for collective dynamics of simple liquids has been applied to compute various dynamical properties of liquid Na: detailed dynamical structure factors, current–current correlation functions, dispersion relation, velocity of sound, and the diffusion coefficient, at a temperature that is fairly above the melting point (323 K) and hence, comprises a classical system of interacting particles whose motions are strongly correlated. The detailed coherent dynamical structure factors, \(S(k,\omega )\), and the current–current correlation functions have been evaluated for a huge wave vector, \(\kappa\), range: 2.5 nm⁻¹ ≤ \(\kappa\) ≤ 88.0 nm⁻¹ and have further been analysed to deduce the dispersion curve and the velocity of sound in the correlated fluid for the entire range of \(\kappa\). The computed dynamical structure factors and the dispersion curve exhibit typical patterns of variation. The velocity of sound is found to align with the experimental result as \(\kappa\) approaches zero. The modified microscopic theory, therefore, is an ample approach that makes use of inter-particle interactions to determine the dynamical behaviour of a given fluid. The computed dynamical structure factors are applied with quantum corrections due to the detailed balance condition, which are found to be perceptible for higher \(\omega\) values.