- Nothing amuses more harmlessly than computation and nothing is oftener applicable to real business or speculative enquiries. A thousand stories which the ignorant tell, and believe, die away at once, when the computist takes them in his grip.
- Samuel Johnson
CASTEP is a leading code for calculating the properties of materials from first principles. Using density functional theory, it can simulate a wide range of properties of materials proprieties including energetics, structure at the atomic level, vibrational properties, electronic response properties etc. In particular it has a wide range of spectroscopic features that link directly to experiment, such as infra-red and Raman spectroscopies, NMR, and core level spectra.
Suppression of thermal conductivity by rattling modes in thermoelectric sodium cobaltate Thermoelectric materials are found in applications from waste energy recovery to solid-state refrigeration. Their performance is characterised by a figure-of-merit which is inversely proportional to thermal conductivity, and is highest in materials with low-frequency, anharmonic "rattler" modes. A joint experimental and computational investigation of the phonon spectrum of sodium cobaltate reveals low frequency Einstein-like modes with small dispersion across the Brillouin Zone. ref.