## Software

# ABINIT

ABINIT is a suite of programs for materials science, which implements density functional theory, using a plane wave basis set and pseudopotentials, to compute the electronic density and derived properties of materials ranging from molecules to surfaces to solids. It implements density functional theory by solving the Kohn–Sham equations describing the electrons in a material, expanded in a plane wave basis set and using a self-consistent conjugate gradient method to determine the energy minimum. Computational efficiency is achieved through the use of fast Fourier transforms, and pseudopotentials to describe core electrons. As an alternative to standard norm-conserving pseudopotentials, the projector augmented-wave method may be used. In addition to total energy, forces and stresses are also calculated so that geometry optimizations and ab initio molecular dynamics may be carried out. Materials that can be treated by ABINIT include insulators, metals, and magnetically ordered systems including Mott-Hubbard insulators.

# Atomic Simulation Environment (ASE)

The Atomic Simulation Environment (ASE) is a set of tools and Python modules for setting up, manipulating, running, visualizing and analyzing atomistic simulations.

# CONUSS

The CONUSS software package provides evaluation methods for data obtained by nuclear resonant scattering techniques. It is used for the interpretation of time or energy spectra from coherent elastic nuclear resonant scattering, i.e., forward scattering and Bragg/Laue scattering,

# Crispy

Crispy is a modern graphical user interface to simulate core-level spectra using semi-empirical multiplet approaches.

# CRYSTAL

Computational tool for solid state physics and chemistry. The CRYSTAL package performs ab initio calculations of the ground state energy, energy gradient, electronic wave function and properties of periodic systems. Hartree-Fock or Kohn- Sham Hamiltonians (adopting an Exchange-Correlation potential following the DFT postulates of ) can be used. Systems periodic in 0 (molecules, 0D), 1 (polymers, 1D), 2 (slabs, 2D), and 3 dimensions (crystals, 3D) are treated on an equal footing. In each case the fundamental approximation made is the expansion of the single particle wave functions ('Crystalline Orbital', CO) as a linear combination of Bloch functions (BF) defined in terms of local functions, i.e. Atomic Orbitals.

# DAWN

DAWN, the Data Analysis WorkbeNch, is an Eclipse based application for scientific data analysis. It comes with a range of tools for visualization (1D, 2D and 3D), code development environments (for Python, Jython and Eclipse plug-ins) as well as processing workflows with visual algorithms for analyzing scientific datasets. It is primarily developed at Diamond Light Source, but external contributions are most welcome! DAWN is distributed freely and is released under the Eclipse Public License.

# FDMNES

The aim of the FDMNES project is to supply to the community a user friendly code to simulate x-ray spectroscopies, linked to the real absorption (XANES, XMCD) or resonant scattering (RXD) of the synchrotron radiation. This ab initio approach, wants to eliminate all the methodological parameters. First mainly mono-electronic, using the functionnal density theory (DFT), it includes now multi-electronics advances with the use of the time dependant DFT (TD-DFT) for a better taking into account of the excited states linked to the photon-matter interaction. It includes also the Hubbard correction (LDA+U) for a better description of the so called correlated materials.

# FEFF9

Condensed matter code for modelling x-ray and electron spectroscopies and materials properties. FEFF is an automated program for ab initio multiple scattering calculations of X-ray Absorption Fine Structure (XAFS), X-ray Absorption Near-Edge Structure (XANES) and various other spectra for clusters of atoms. The code yields scattering amplitudes and phases used in many modern XAFS analysis codes, as well as various other properties. in FEFF9 there are several new spectroscopies which can be calculated with FEFF 9, including electron energy loss spectra (EELS) and non-resonant inelastic x-ray scattering (NRIXS). In addition, there are a variety of improvements. These include; (1) ab initio Debye-Waller factors; (2) improved treatment of inelastic losses; (3) an improved treatment of the core-hole interaction; and (4) more accurate treatment of crystalline systems with k-space calculation of the Green's function. FEFF9 comes with the JFEFF GUI.

# Frida

Frida (“Fast reliable interactive data analysis”) is a versatile data analysis program with special routines for inelastic neutron scattering.

# iFit

The iFit library (pronounce [eye-fit]) is a set of methods to load, analyse, plot, fit and optimize models, and export results. iFit is based on Matlab, but can also be launched without Matlab license (stand-alone version).Matlab It does not currently include advanced graphical user interfaces (GUI), and rather focuses on doing the math right. Any text file can be imported straight away, and a set of binary files are supported. Any data dimensionality can be handled, including event based data sets (even though not all methods do work for these). Any model can be assembled for fitting data sets. Last, a number of routines are dedicated to the analyses of S(q,w) and S(alpha,beta). More advanced features include the full automation to compute phonon dispersions in materials, using DFT codes such as ABINIT, ELK, VASP, QuantumEspresso, GPAW and more (Models/sqw_phonons). The software can also compute the neutron TAS resolution function (4D) and fits to experimental data with full resolution convolution (ResLibCal). An interface for McStas and McXtrace is also available to automate and optimize instrument simulations.

# Materials Studio

Materials Studio is a modeling and simulation environment designed to allow to predict and understand the relationships of a material’s atomic and molecular structure with its properties and behavior. With it one can construct, manipulate and view models of molecules, crystalline materials, surfaces, polymers, and mesoscale structures. Materials Studio includes quantum, atomistic (or “classical”), mesoscale, and statistical methods that enable one to evaluate materials at various particle sizes and time scales. It also includes tools for evaluating crystal structure and crystal growth.

# McStas

A neutron ray-trace simulation package. McStas is a general tool for simulating neutron scattering instruments and experiments.

# OCEAN

OCEAN is a versatile package for performing first-principles calculations of core edge spectroscopy. The many-body method is based on ground-state density-functional theory (DFT) and uses the Bethe-Salpeter equation. OCEAN utilizes the programs ABINIT or QuantumESPRESSO for ground-state DFT portion of the calculations. OCEAN is capable of producing various spectra including X-ray absorption near-edge spectra (XANES), X-ray emission spectra (XES), and non-resonant inelastic X-ray scatter (NRIXS or XRS). OCEAN is the result of collaboration between the Rehr group at the University of Washington and Eric Shirley at the National Institute of Standards and Technology (USA).

# Quantum Espresso

Quantum ESPRESSO (QE) is an integrated suite of Open-Source computer codes for ab initio quantum chemistry methods of electronic-structure calculations and materials modeling at the nanoscale. It is based on density functional theory, density functional perturbation theory, plane wave basisi sets, and pseudopotentials. The core plane wave DFT functions of QE are provided by the PWscf (Plane-Wave Self-Consistent Field) component,

# Quanty

Quanty is a script language which allows the user to program quantum mechanical problems in second quantization and when possible solve these. It can be used in quantum chemistry as post Hartree-Fock or in one of the LDA++ schemes. (self consistent field, configuration interaction, coupled cluster, restricted active space, ...) The idea of Quanty is that the user can focus on the model and its physical or chemical meaning. Quanty takes care of the mathematics.