The mod- n scheme is introduced to the coupled-cluster singles and doubles (CCSD) and third-order Møller-Plesset perturbation (MP3) methods for extended systems of one-dimensional periodicity. By downsampling uniformly the wave vectors in Brillouin-zone integrations, this scheme accelerates these accurate but expensive correlation-energy calculations by two to three orders of magnitude while incurring negligible errors in their total and relative energies. To maintain this accuracy, the number of the nearest-neighbor unit cells included in the lattice sums must also be reduced by the same downsampling rate (n). The mod- n CCSD and MP3 methods are applied to the potential-energy surface of polyethylene in anharmonic frequency calculations of its infrared- and Raman-active vibrations. The calculated frequencies are found to be within 46 cm-1 (CCSD) and 78 cm-1 (MP3) of the observed.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Sep 7 2010|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics