Elastic Constants and Lattice Vibrations of Pd₀․₉₅Rh₀․₀₅ Alloy

Phonon dispersion relations along the [0,0, q], [0, q, 1], [0, q, q], and [q, q, q] directions of face-centered cubic Pd₀․₉₅Rh₀․₀₅ have been studied within the framework of the pseudopotential method. Without phenomenological fitting in real space, a transition-metal pseudopotential that is directly derived from generalized pseudopotential theory (GPT) has been used. This potential has been used to compute bulk modulus (B), elastic constants (C₁₁, C₁₂, and C₄₄) and phonon dispersion curves along symmetry directions. Both solid and liquid metal properties can be effectively described by the selected pseudopotential. The calculated results show excellent agreement with existing experimental data, validating the reliability of the current methodology for Pd–Rh alloys. The study indicates that increasing Pd concentration in Pd–Rh alloys lead to a consistent improvement of elastic constants and bulk modulus, highlighting the stiffening effect of Pd on the alloy system.