NanoGW is an open-source software package to perform linear-response time-dependent density functional theory, GW, and Bethe-Salpeter equation calculations based on the solution of the Casida equation employing a real-space grid targeting confined systems such as molecules and clusters. The NanoGW code is available at http://real-space.org/downloads/. This package can perform the following calculations:
- Linear-response time-dependent density functional theory (by solving Casida equation)
- Full-frequency GW calculation with or without LDA vertex function (does not support spin-orbit coupling)
- Construct and solve Bethe-salpeter equation
This package has been tested thoroughly and optimized for molecules and nanoclusters. It runs particularly efficient for small-size (less than 30 atoms) molecules or clusters. This package can also deal with crystalline systems. However, its functionality for dealing crystals has not been thoroughly tested yet.
This package requires wave functions and Kohn-Sham energies calculated with PARSEC as input. It also support plane-wave based DFT package PARATEC. NanoGW will convert the plane-wave based wave functions to real-space based wave functions. However, its compatibility with PARATEC has not been thoroughly tested yet.
NanoGW is developed in tandem with the DFT code PARSEC. PARSEC is a computer code that solves the Kohn-Sham equations by expressing electron wave-functions directly in real space, without use of explicit basis set. The name stands for “Pseudopotential Algorithm for Real-Space Electronic Calculations”. It handles one-dimensional and three-dimensional periodic boundary conditions and confined-system boundary conditions. PARSEC is also available at: http://real-space.org/downloads/.