Physical Review B 84, 165131 (2011)

Calculating optical absorption spectra for large systems using linear-scaling density functional theory

Laura E. Ratcliff, Nicholas D. M. Hine and Peter D. Haynes

Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom


A new method for calculating optical absorption spectra within linear-scaling density functional theory (LS-DFT) is presented, incorporating a scheme for optimizing a set of localized orbitals to accurately represent unoccupied Kohn-Sham states. Three different schemes are compared and the most promising of these, based on the use of a projection operator, has been implemented in a fully functional LS-DFT code. The method has been applied to the calculation of optical absorption spectra for the metal-free phthalocyanine molecule and the conjugated polymer poly(para-phenylene). Excellent agreement with results from a traditional DFT code is obtained.


Last updated: 27 October 2011