# Tag Info

19

"Matter modeling" is a term that was coined by Stack Exchangers! That's why the words "matter" and "modeling" next to each other, don't seem to exist in any of the results in a Google search of "Matter Modeling", apart from this Stack Exchange site, Adam Iaizzi's blog post about this SE site, and maybe our community's ...

15

What is a force field? The Wikipedia entry on this is a good resource, but I'll give my own description below. In the context of molecular dynamics (MD), a force field is one way of describing the interactions between atoms. In classical MD, the motion of atoms is determined by the instantaneous forces acting on the atoms (i.e., we need forces in order to ...

11

I don't think it's ideal, but there is the term "base metal". There are various definitions for what is considered a base metal, but the main noble (or precious) metals are always excluded. Some definitions also exclude ferrous metals. Unfortunately, this variation in meaning means it might be better to just say "non-ferrous, non-noble", ...

10

First of all, we assume the matter is constituted by nuclei and electrons, as illustrated by the following figure: Mathematically, the matter is mapped into the following Hamiltonian: $$H=T_e + T_n + V_{ee} + V_{nn} + V_{en} \tag{1}$$ which is called the standard model of condensed matter physics. In principle, all information (ground state/excited state/...

7

The term's origin goes back to vector field which is a function that returns a vector for any given point in space (as in the image below on the left). We can almost "see" that such fields exist, by putting iron filings and a magnet on a sheet of paper (the magnetic field causes the iron filings to move accordingly): In classical molecular ...

6

Molecular dynamics is based in Molecular Mechanics. Molecular Mechanics do many approximations in order to treat the atomic/molecular system. A good definition can be seen here: Molecular Mechanics is a computational method that computes the potential energy surface for a particular arrangement of atoms using potential functions that are derived using ...

6

Independent of facing a 3D sample, or one of 2D/2.5D, IUCr's definition applies to both of them when stating «There are two definitions of the notion of quasicrystal. A quasicrystal is an aperiodic crystal that is not an incommensurate modulated structure, nor an aperiodic composite crystal. Often, quasicrystals have crystallographically 'forbidden' ...

6

This 2017 paper titled "Shape and Energy Consistent Pseudopotentials for Correlated Electron systems" defines energy-consistent psuedopotentials this way: "A combined reproduction of core scattering, core polarisation, and atomic excitation energies allows the generation of a new pseudopotential from correlated electron calculations, referred ...

6

When your lattice is primitive you have only the (0,0,0)+ set; when your lattice has some kind of centering (body- or face-centering) other sets are present, such as (1/2, 1/2, 1/2)+ or (1/2, 1/2, 0)+ It's not clear to me what you write. In the first page of the Internationl Tables you find all the symmetry operations that are listed with Roman numerals (1),(...

5

The "pn" column here gives the principal quantum number ("n") for the states of the pseudoatom, which is the "atom" that remains after the core electrons are removed and the original Coulomb potential is replaced with the pseudopotential. For example, in the file you show, the $n=1$, $l=0$ state of the pseudo-atom corresponds to ...

4

Not only do I agree with the comments by TheSimpliFire, S R Maiti, and wzkchem5, that there is likely no word for this in English; I'll also go as far as to say that even the German word you suggested does not precisely fit your description of being "non-ferrous and non-noble". "Buntmetalle" just means "colorful metals". The ...

4

Got a bit too long for a comment, so I'll leave it as a semi-complete answer for now. In case the paper is inaccessible to other readers, much of the same information is in the gulp5.2 manual. In regards to the question, it does seem to elaborate a little in the sentences following your quote. From earlier in the document: Here the Coulomb interaction, and ...

4

Take care in the figure posted by Jack that the [hkl] notation actually represents the vector plane, that is the direction perpendicular to the plane. The plane are indexed as (hkl). for example, the first figure should be read as (001) plane of NaCl, whereas [001] represents the direction along the c-axis.

3

In short, the polarization catastrophe is the fact that the classical description of polarization applied to point dipoles contains a singularity which occurs at a distance which should regularly be sampled in the course of ordinary classical dynamics. More specifically, the polarization catastrophe is the failure that happens when one tries to describe the ...

3

From the Wiki page, the density of states (DOS): In solid state physics and condensed matter physics, the density of states (DOS) of a system describes the proportion of states that are to be occupied by the system at each energy. The density of states is defined as $D(E) = N(E)/V$, where $N(E)\delta E$ is the number of states in the system of volume $V$ ...

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