RMC-8(+1) Conference, Budapest

Probing NiO lattice dynamics by X-ray absorbtion spectroscopy combined with reverse Monte Carlo method

23 Sept 2023, 11:30

30m

room 103 (Central European University, CEU Nador 15 Campus (Budapest, Hungary))

Sa2

Speaker

Julija Lukasevica (Institute of Solid State Physics, University of Latvia, Latvia)

Description

Lattice dynamics of bulk NiO was studied at seven temperatures from 10 K to 300 K using the Ni K-edge X-ray absorption spectroscopy combined with the reverse Monte Carlo simulations. Lattice dynamics calculations with empirical potential were also performed for comparison. The potential model was validated by comparing the experimental Ni K-edge extended X-ray absorption fine structure (EXAFS) spectrum of NiO with the results of molecular dynamics simulations at 300 K.
As a result of both calculation methods, the mean-square relative displacements (MSRDs) for Ni-O and Ni-Ni atom pairs were determined, showing their temperature and interatomic distance dependencies. An unexpected increase in the MSRD values for O atoms in the 3rd coordination shell of nickel was observed.