# Tag Info

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OpenMOLCAS I'm surprised that the other two answers were given without yet any mention of OpenMOLCAS yet! There is a recent paper[1] about it for which I happen to be one of the many co-authors. MOLCAS has the quality of a commercial software like MOLPRO, since it was a commercial software that people paid big money for since the 1980s, but recently an open ...

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Julia The answers above allude to what some call the "two-language problem". In materials science it takes the form of writing your code in Fortran for speed, and writing an interface to it in Python for sanity and interactivity. Fortran will not go away any time soon due to the massive amount of legacy code available. For new codes, there is a new ...

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There isn't a silver bullet for this, so in my humble opinion there isn't a "best" Linux distribution for this. Just as Kali is not "the best" for security and Scientific Linux is also not advertised as the "best" for HEP. They are just good enough alternatives that tackle some issues that may seem helpful for many users, such as including many things and ...

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Fortran A large part of materials modelling involves density functional theory and molecular mechanics. From this compilation of quantum chemistry software, the most widely used programming language seems to be Fortran. Indeed, the popular packages VASP (commercial), Quantum Espresso and Siesta (both free) all use this language.

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2006 (Grimme): Double hybrid functionals The timeline of milestones you have given, includes a hybrid functional called B3LYP, which mixes a Hartree-Fock exchange functional with a GGA exchange-functional. In 2006, Stefan Grimme introduced what later became known as "double hybrid functionals", which not only mix the Hartree-Fock exchange functional with a ...

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2015 (Sun et al.): SCAN functional The SCAN meta-GGA functional is an extension of the popular PBE GGA [1] and the TPSS [2] and revTPSS [3] meta-GGAs, SCAN adheres to all 17 known exact XC constraints and is constructed to be almost exact for the noble gasses and jellium surfaces. Early evidence suggests that SCAN is more accurate than and of comparable ...

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ORCA ORCA (forum). It is fully featured, efficient, and free for academics. The input is straightforward: # CASSCF(2,4) example from the manual, # section 8.1.7.2, page 108 ! TZVPP TightSCF %casscf nel 2 norb 4 end * xyz 0 1 Be 0 0 0 * Some resources for CASSCF: General functionality is reported in this tutorial. A tutorial dedicated exclusively to ...

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It depends on what you want to do I'll go first. For context: I do mostly Monte Carlo simulations, especially quantum Monte Carlo. My work has focused on spin systems, using techniques like the Metropolis Algorithm and stochastic series expansion QMC. For Writing Simulations: In my field there are few software packages available and the algorithms are ...

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Julia Okay, I have to add Julia. Everyone is saying Fortran or Python, and I love them both, but they both have issues. Fortran is easy for a compiled language to write, but I still have SIGSEGV burned into my retinas. Python is fast to write, but very slow. Learning how to cleverly make python fast (and it is still not all that fast) takes more time and ...

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Canada: Compute Canada Before Compute Canada (Antiquity) Supercomputing in Canada began with several disparate groups: 1997: MACI (Multimedia Advanced Comp. Infrastructure) is formed from Alberta universities. 2001: WestGrid is formed by 7 Alberta and BC institutions (facilities launched in 2003). 1998: HPCVL is formed by institutions in Toronto and ...

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Python @taciteloquence has already mentioned Python for data analysis and visualization, but let me add one more angle: automation. Simulation nowadays often means high-throughput, automated simulation. Not only for large scale projects, like Materials Project but also individual projects where large amounts of data generated for screening properties, ...

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I will start with acronyms for coupled-cluster, and someone else might answer with acronyms for basis sets or for functionals or for many body perturbation theory or for composite approaches or for different types of SCF: Coupled Cluster acronyms CCSD, CCSDT, CCSDTQ, ... (coupled cluster with singles, doubles, triples, quadrtuples, etc.) CCSD(T), CCSDT(Q), ...

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Blender I usually do 3D images with molecules using Blender. You can export your molecule 3D model with a chemistry visualization program (such as vmd or jmol) into Blender (I usually do it using OBJ files, it just needs a couple of adjustments after the import), OR you can write your own python loader from within Blender (harder to do, but possible). It is ...

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2013: Density-Corrected DFT (DC-DFT) The goal of Density-Corrected DFT (DC-DFT) is not only to get better accuracy but also to understand and correct the true error in the functional approximation.[1,2] In any approximate density functional, the DFT error is $\Delta E = \tilde E[\tilde n] - E[n]$ where $E$ and $n$ are exact functional and density while $\... 20 USA: Facilities funded by NSF XSEDE (Extreme Science and Engineering Discovery Environment) XSEDE (pronounced like "exceed") provides access to both computational resources and trainings on HPC. These may be especially useful if your institution does not provide good support for scientific computing. From their website: XSEDE provides live and ... 19 2004 (Yanai et al.): Range separation Often, the source of DFT improvement comes from Hartree-Fock as is also obvious from the answer involving double hybrid functionals. So too it is with range-separation. The electron-electron Coulomb operator for the exchange contribution is separated into a short and long range contribution. \frac{1}{... 19 It depends on what you want to do I think one major question that needs to be asked is "What do you want to do?". Develop new quantum chemistry codes? Use them more efficiently? Automate data processing? User @taciteloquence Has given a good answer I think. Many legacy codes are written in Fortran - newer codes will be typically written in C or C++.... 19 Fedora Susi Lehtola's answer makes some good points, and I will elaborate on two of them: The Linux distributions mentioned in your question, which cater to specific communities (e.g. Scientific Linux for particle physics, MathLibre for math, Kali Linux for cybersecurity) are descendants of much more widely-known distributions, so they are not acutely ... 19 Ubuntu For your workstation or laptop the best linux distribution is Ubuntu. Many of the recommendations here, like CentOS, are great for servers, but you might also have a laptop or desktop computer that you use for developing your code and running simulations. Ubuntu has gone much further than other linux distributions in developing a consumer-grade user ... 19 Just to add to the discussion: Mulliken charges are flawed in many aspects, but we know how and why, and therefore we accept its use, since it is simple and easily computed. But very dependent on the size of the basis set. Mulliken charges do not reproduce the dipole (or higher) moment, but can be made to do so easily: Thole, van Duijnen, "A general ... 19 As previously stated, arguably the most mature and widely used set of tools is currently a combination of Pymatgen, FireWorks, Custodian, and Atomate (which is built upon the prior three Python packages). These tools were constructed as part of the Materials Project but have seen uses in other high-throughput DFT studies. Another general workflow package for ... 19 VMD can load STL files in text (ASCII) format. Here's how I produced the image below: Downloaded STL file of teapot from Wikipedia. This STL file is in binary format, so I used MeshLab to convert it into text format. I opened MeshLab and did File -> Import Mesh and selected the file Utah_teapot_(solid).stl. I then did File -> Export Mesh As and ... 18 It depends on what you want to do It depends on what you want to do. As a couple of others have pointed out, many of the computer programs used in computational chemistry and theoretical solid state physics are written in Fortran. However, that does not imply that you should learn Fortran and it does not mean that Fortran is the best language for materials ... 18 1993 (Becke): Hybrid Functionals Axel D. Becke introduced the adiabatic-connection model, which allows for mixing of DFT exchange and Fock-like exchange via the formula $$E_{\text{x}} = a \cdot E^{\text{HF}}_x + b \cdot E^{\text{GGA}}_x$$ to obtain the exchange part of the exchange-correlation energy. Typically, one imposes$a+b = 1$, but some authors ... 18 LAMMPS LAMMPS provides pre-compiled Windows binaries. You can download them here. 18 United Kingdom (Great Britain) ARCHER (Advanced Research Computing High End Resource) ARCHER is as of today the UK's national supercomputing service, run by the EPCC (Edinburgh Parallel Computing Centre). It has been operating since late 2013, and is based around a Cray XC30 supercomputer. Note, however, ARCHER is right at the end of its lifecycle. It was ... 18 Use of outdated methods Susi Lehtola has given a good answer, to which I would add: Do not use outdated methods. The fact that B3LYP/6-31G* calculations$^1\$ are fast and ubiquitous is exactly zero justification to run them for publication-level work. Take care to evaluate more than one functional and search for benchmark studies of related systems/properties ...

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GIMP Whereas Adobe Photoshop has become so famous as a photo editing software, that we often use the term "photoshopped" to describe an image that's been edited, it is very expensive and GIMP is often called "the free Photoshop". Advantages: Free and open source Works on Linux, MacOS, Windows. Easy to install: sudo apt-get install gimp ...

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1995 (Casida): TD-DFRT Time-Dependent Density Functional Response Theory is a linear response formulation of TDDFT for the calculation of excitation energies and corresponding transition amplitudes, that in turn allows to evaluate electronic spectra of molecular and condensed matter systems. The time-dependent density functional theory (TDDFT) in the Kohn–...

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