Computational Modelling Group

Seminar  13th April 2012 4 p.m.  27:2001

First-principles vibrational spectroscopy and lattice dynamics of materials in the solid state

Dr Keith Refson
Computational Materials Science Group, Rutherford Appleton Laboratory

Bioinformatics, Biomathematics, CASTEP, Complex Systems, Computer Science, CVS, Emacs, FFT, Finite differences, Fortran, Gaussian, HECToR, HPCx, Iridis, Linux, Materials, Metals, Micromagnetics, Molecular Dynamics, Molecular Mechanics, Monte Carlo, Multi-physics, Multi-scale, Multigrid solvers, Multipole methods, NWCHEM, Oceanography, Onetep, ParaView, Povray, Quantum Chemistry, Semiconductors, Software Engineering
Chris-Kriton Skylaris

Raney Ni spectra


Vibrational spectroscopy using light or neutron scattering is a powerful probe of the dynamics and structure of materials, but limited by difficulties of assignment and interpretation. Well-known periodic DFT methods using a plane-wave basis set and pseudopotentials have been extended and combined with lattice dynamics to enable modelling of a wide range of spectroscopy experiments. By completing the missing link between structure and properties, first-principles modelling has become essential to the interpretation of IR, Raman, and inelastic neutron and X-Ray experiments.

I will outline the current state of lattice dynamical and spectroscopy modelling in periodic density functional theory, and highlight some future developments. I will discuss several applications to hydrogen transport in light-metal alloys, in-situ INS studies of Raney Ni catalysts, solid state phase transitions in C60.

A new application of first-principles lattice dynamics is the modelling of thermal diffuse scattering as measured in X-Ray and neutron diffraction experiments. Contributions to scattering at non-Bragg momentum transfer arising from thermal phonons are modelled using first principles DFT. This allows for the first time a complete picture of the results of X-Ray and neutron diffraction experiments using modern area detectors.