# About SALMON

## Contents

## What is SALMON

SALMON is an open-source computer program for ab-initio quantum-mechanical calculations of electron dynamics at the nanoscale that takes place in various situations of light-matter interactions. It is based on time-dependent density functional theory, solving time-dependent Kohn-Sham equation in real time and real space with norm-conserving pseudopotentials.

SALMON was born by unifying two scientific programs: ARTED, developed by Univ. Tsukuba group, that describes electron dynamics in crystalline solids, and GCEED, developed by Institute for Molecular Science group, that describes electron dynamics in molecules and nanostructures. It can thus describe electron dynamics in both isolated and periodic systems. It can also describe coupled dynamics of electrons and light-wave electromagnetic fields.

To run the program, SALMON requires MPI Fortran/C compiller with LAPACK libraries. SALMON has been tested and optimized to run in a number of platforms, including Linux PC Cluster with x86-64 CPU, Fujitsu FX100 supercomputer system, K-computer, and supercomputer system with Intel Xeon Phi (Knights Landing).

## What can SALMON do

SALMON describes electron dynamics in both isolated (molecules and nanostructures) and periodic (crystalline solids) systems. SALMON first carries out ground-state calculations in the density functional theory to prepare initial configurations. SALMON then calculates electron dynamics induced by applied electric field. Employing a weak impulsive external field, SALMON can be used to calculate linear response properties such as a polarizability of molecules and a dielectric function of crystalline solids. Using pulsed electric fields, SALMON describes electron dynamics in matters induced by intense and ultrashort laser pulses.

### Ground state calculations

- Kohn-Sham orbitals and energies
- density of states
- projected density of states
- electron localization function

### Optical properties

- Oscillator strength distribution (absorption spectrum)
- dielectric function

### Light-induced electron dynamics

- time evolution of Kohn-Sham orbitals
- density, current
- excitation energy
- number density of excited carriers

### Simultaneous description of electron dynamics and light pulse propagation

- light pulse propagation as well as time evolution of Kohn-Sham orbitals
- energy transfer from pulsed light to electrons

## License

SALMON is available under Apache License version 2.0.

Copyright 2017 SALMON developers Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.