The BerkeleyGW package is a set of computer codes that calculates the quasiparticle properties and the optical responses of a large variety of materials from bulk periodic crystals to nanostructures such as slabs, wires and molecules.

The package takes as input the mean-field results from various electronic structure codes such as the Kohn-Sham DFT eigenvalues and eigenvectors computed with PARATEC, Quantum ESPRESSO, SIESTA, PARSEC, Abinit, Octopus, or TBPW (aka EPM). The package consists of the three main component codes:

- Epsilon computes the irreducible polarizability in the Random Phase Approximation and uses it to generate the dielectric matrix and its inverse.
- Sigma computes the self-energy corrections to the DFT eigenenergies using the GW approximation of Hedin and Lundqvist, applying the first-principles methodology of Hybertsen and Louie within the generalized plasmon-pole model for the frequency-dependent dielectric matrix.
- BSE solves the Bethe-Salpeter equation for correlated electron-hole excitations.

When using BerkeleyGW, you are expected to cite the following papers and acknowledge the use of the BerkeleyGW package in your publications.

- Mark S. Hybertsen and Steven G. Louie, “Electron correlation in semiconductors and insulators: Band gaps and quasiparticle energies,” Phys. Rev. B 34, 5390 (1986)
- Michael Rohlfing and Steven G. Louie, “Electron-hole excitations and optical spectra from first principles,” Phys. Rev. B 62, 4927 (2000)
- Jack Deslippe, Georgy Samsonidze, David A. Strubbe, Manish Jain, Marvin L. Cohen, and Steven G. Louie, “BerkeleyGW: A Massively Parallel Computer Package for the Calculation of the Quasiparticle and Optical Properties of Materials and Nanostructures,” Comput. Phys. Commun. 183, 1269 (2012)(http://arxiv.org/abs/1111.4429)

Papers #1 and #3 should be cited when discussing quasiparticle properties, and papers #2 and #3 should be cited when discussing optical properties.

## Usage

The main steps in a BerkeleyGW calculation are:

- GW calculation:
- Bethe-Salpeter equation (BSE) caclculation:
`kernel`

- calculating the electron-hole interaction`absorption`

- evaluate optical and excited-state properties.

#PBS -l walltime=00:10:00 #PBS -l mem=1GB #PBS -l ncpus=4 #PBS -l wd module load BerkeleyGW/2.0.0 mpirun PROGRAM > OUTPUT