Programme

P.92 -- Posters, VCTP-50

Date: Thursday, 7 August 2025

Time: 08:30 - 10:00

Anharmonic high-order XAFS cumulants of crystalline silver within quantum-statistical perturbation theory

Le Viet Hoang (1), Tong Sy Tien (2), Nguyen Thi Minh Thuy (2,3), Nguyen Huy Thao (3), Nguyen To Nu (3), Nguyen Cong Toan (1)

(1) Hanoi University of Science, (2) University of Fire Prevention and Fighting, (3) Hanoi Pedagogical University 2

The anharmonic high-order X-ray absorption fine structure (XAFS) cumulants of crystalline silver (Ag) have been theoretically analyzed with explicit consideration of thermal disorder effects. The proposed model is formulated based on the first-order perturbation approach within the framework of quantum statistical theory, incorporating the correlated Einstein model and an anharmonic effective potential that characterizes atomic interactions. The resulting thermodynamic XAFS parameters account for both atomic correlation and anharmonicity, explicitly including the influence of nearest-neighbor atoms on the absorber and backscatter. The temperature-dependent expressions are derived in explicit analytical form, accurately describing the physical behavior in both low- and high-temperature regimes. Numerical calculations for Ag exhibit good agreement with available experimental data and other theoretical models throughout the temperature range of 0–1000 K. These results confirm that the present theoretical framework is effective for analyzing anharmonic high-order XAFS cumulants in thermally disordered metals, particularly those exhibiting complex thermal dynamics. Keywords: Anharmonic high-order XAFS cumulants, crystalline silver, quantum-statistical perturbation theory, thermal disorder

Presenter: Lê Việt Hoàng