  SALMON (Scalable Ab-initio Light-Matter simulator for Optics and Nanoscience,
http://salmon-tddft.jp) is a software package for the simulation of electron
dynamics and optical properties of molecules, nanostructures, and crystalline
solids based on first-principles time-dependent density functional theory. The
core part of the software is the real-time, real-space calculation of the
electron dynamics induced in molecules and solids by an external electric field
solving the time-dependent Kohn-Sham equation. Using a weak instantaneous
perturbing field, linear response properties such as polarizabilities and
photoabsorptions in isolated systems and dielectric functions in periodic
systems are determined. Using an optical laser pulse, the ultrafast electronic
response that may be highly nonlinear in the field strength is investigated in
time domain. The propagation of the laser pulse in bulk solids and thin films
can also be included in the simulation via coupling the electron dynamics in
many microscopic unit cells using Maxwell's equations describing the time
evolution of the electromagnetic fields. The code is efficiently parallelized
so that it may describe the electron dynamics in large systems including up to
a few thousand atoms. The present paper provides an overview of the
capabilities of the software package showing several sample calculations.
