CASTEP is a leading code based on planewave-pseudopotential density functional theory. CASTEP can calculate a plethora of properties from first-principles, including energies, vibrational properties (such as infra-red and Raman spectra), electronic response properties, NMR parameters and more. A more complete list of CASTEP functionality is available here.
CASTEP is available for academic use under a recently agreed cost-free worldwide source code license. For further information and for research-group license forms, see the CASTEP website.