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Questions tagged [physical-properties-of-materials]

Questions about modeling or theoretical/computational values for physical properties of materials such as ductility, Young's modulus, malleability, conductivity, specific heat capacity, density, etc.

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20 votes
3 answers
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Are there dashboards displaying experimental properties of molecular materials?

A dataset is generally a collection of data. A database is an organized collection of data, allowing different kinds of queries. A dashboard is a graphical user interface that is employed to make ...
agaitaarino's user avatar
  • 1,501
17 votes
2 answers
135 views

Can ab initio crystal structure methods predict the structure of cuprates from their stoichiometry and quantify the brittleness of those materials?

Current ab initio methods may not be able to predict the electronic transport properties of cuprate superconductors but can they be used to predict their crystal structure? Furthermore those materials ...
pldd86's user avatar
  • 579
14 votes
1 answer
146 views

What are the physical consequences of adding a constant to the diagonal of the effective Hamiltonian of monolayer materials?

Effective Hamiltonians modeling many-layered materials are often tuned using some sort of bias voltage. For instance, in a $4\times 4$ Hamiltonian matrix to describe biased bilayer graphene using some ...
TribalChief's user avatar
  • 2,351
13 votes
1 answer
161 views

Has a form of diamond with certain properties ever been theorized?

The following is what a Penrose tiling looks like: I know the verticies of a dodecahedron can be grouped into 5 groups each of which are the verticies of a tetrahedron. So I thought of the idea that ...
Timothy's user avatar
  • 479
13 votes
0 answers
96 views

A viscoelastic material with nonconvex memory kernel?

The title is basically my question. Viscoelastic materials are characterized by a constitutive equation between stress and strain involving a convolution integral. This integral is weighted with a ...
ALive's user avatar
  • 131
12 votes
1 answer
2k views

Selection of appropriate Langevin damping parameter for MD of solid metal

I am performing an MD simulation involving solid metal. The system is in the NVT ensemble, and I am using the Langevin thermostat (fix Langevin in LAMMPS) to enforce this. I have previously used the ...
anneb101's user avatar
  • 995
12 votes
1 answer
179 views

How can one computationally determine the flammability of a molecular system?

I can imagine one aspect of flammability (the ability of a substance to ignite on fire) to include calculating the kinetics and thermodynamics of the reaction of the system with oxygen. This is not ...
BernhardWebstudio's user avatar
11 votes
1 answer
424 views

Software recommendations to construct band structures using tight binding

I am at the beginning of computational materials modeling. My objective is to calculate the electrical conductivity of a system that consists of several thousand atoms, and running DFT calculations is ...
wenusara satheekshana's user avatar
11 votes
1 answer
341 views

Calculating hyperpolarizability in NWChem

I'm trying to make a pipeline geometry optimization -> calculation of polarizability/hyperpolarizability. And NWChem seems pretty good for it, the only thing I can't understand its how to calculate ...
Roman's user avatar
  • 2,373
11 votes
1 answer
143 views

How can I quantify the uncertainty of thermal molecule properties in molecular dynamics simulations?

When doing molecular dynamics simulations, there are countless sources of error (i.e. approximations and numerics). Molecular dynamics can be used to determine intrinsic thermal properties such as ...
BernhardWebstudio's user avatar
11 votes
1 answer
177 views

How can we make a mechanically unstable cubic system, stable

I have to calculate the elastic constants of a Cubic system using a Density functional theory-based software. A cubic system will be mechanically stable if it satisfies the Born-stability condition (...
astha's user avatar
  • 1,663
10 votes
2 answers
351 views

Why are my publications getting accepted without much review from some journals, but getting rejected by the journal Computational Materials Science?

My field of research is computational materials science/mechanics. My work is on the "numerical modeling of shot peening process". This is a typical publication in my field. My work is not ...
johdep's user avatar
  • 111
10 votes
0 answers
110 views

Large dataset with conductivities of materials and chemical compounds? [closed]

I'm looking for a fairly large (>100k) dataset of chemical compounds (and materials) that has conductivities. I've looked at PubMed, but couldn't find conductivities. I would ideally like to avoid ...
explodingfilms101's user avatar
10 votes
0 answers
165 views

How can I draw the energy bands for the first and second zones of Brillouin? Is it conductor or insulator? [closed]

I want to draw the energy ($E$) diagrams for a simple cubic cell of parameter $a$, where each atom provides two electrons for the almost free electron levels for planes [100], [110] and [111]. I ...
Carmen González's user avatar
9 votes
1 answer
268 views

Comparing results of various DFT calculations in Quantum ESPRESSO

To verify the reliability of calculation scheme, I want to compare lattice constants, bond length and band gap calculated by the different functionals with the experimental results. So in order to do ...
Joyal sunny's user avatar
9 votes
1 answer
3k views

How to use the ev.x tool in Quantum ESPRESSO?

The requirement I have is to calculate the bulk modulus from the energy values at certain volumes obtained via DFT calculations. Can you provide the instructions to use the ev.x tool in the Quantum ...
Anoop A Nair's user avatar
  • 4,476
9 votes
1 answer
226 views

How to find the Cauchy stress tensor in solids using ab-initio methods?

I want to find the Cauchy stress tensor in certain materials with ab initio methods. I already have the analytical form of my own definition of "energy" and "forces" (not from DFT),...
Tack_Tau's user avatar
  • 193
9 votes
1 answer
141 views

Are there other kinds of stability of materials? How to demonstrate that with computation approaches?

I have known some kinds of stability of materials, such as: Mechanical stability; Dynamical stability; Thermal stability In particular, they can be studied with first-principles computational ...
Jack's user avatar
  • 15.1k
9 votes
2 answers
1k views

Calculating lattice thermal conductivity using Quantum ESPRESSO and phonopy

How should I calculate lattice thermal conductivity in Quantum ESPRESSO? I have installed phonopy. My Linux distribution is Ubuntu.
epsilon02fft's user avatar
  • 1,522
9 votes
1 answer
785 views

Why VASP calculates the elastic constant for another trigonal space group?

Please, help me to understand the problem. I calculated the elastic constants for the beta PHB (Space group P3221 (154)), it has to show the reduced elastic constant matrix (six), however, ...
Irina's user avatar
  • 191
9 votes
0 answers
108 views

How to go from zero to hero in Machine Learning for materials modelling

I am interested in exploring the use of machine learning tools to accelerate molecular dynamics simulation probably by training machine learning potentials. While I have found some papers that apply ...
manuelpb's user avatar
  • 453
9 votes
0 answers
108 views

How to calculate the thickness of the slab when simulating a bulk surface? [closed]

The method I found, which seems to be the most commonly used for simulating surfaces, involves constructing a slab and doing a structural optimization by freezing a few of its lowermost layers. What ...
Ashique Lal's user avatar
  • 1,621
9 votes
0 answers
209 views

Is "Valence Electron Density" and "Electron Density" data of a molecule the same thing? [closed]

I'm wondering specifically in the context of calculating physical properties from valence-electron-density data using DFT, MD, and or ML (machine learning).
Pranoy Ray's user avatar
  • 1,683
8 votes
2 answers
470 views

Mathematical models for the plastic region in the tensile test

The tensile test of a material consists of subjecting a standardized specimen to an increasing axial tensile stress until it breaks. During its performance in the laboratory, we can plot a stress-...
Carlos's user avatar
  • 461
8 votes
1 answer
183 views

How to study a new material without any experimental data about it?

My question is a little bit general. I want to study a 2D monolayer material which hasn't any experimental data available, just some first principles DFT works using PBE, LDA and HSE06 (for band ...
Chi Kou's user avatar
  • 5,833
8 votes
1 answer
93 views

What are the possible applications of DIC (digital image correlation) in mechanical testing and the field of materials science?

I would like to know about possible applications of DIC in mechanical testing and the field of materials science, when I search there is the general topics of DIC usages, but I would like to know ...
Sina M's user avatar
  • 81
8 votes
1 answer
450 views

How to calculate the volumetric energy density of a molecule?

I am trying to store hydrogen in a hydrocarbon. The example can be taken as cyclohexane ($\ce{C6H12}$) which is in a hydrogen-rich state. Its hydrogen-lean state is Benzene. I want to calculate the ...
astha's user avatar
  • 1,663
8 votes
1 answer
795 views

Viscosity calculation using molecular dynamics simulations

I use the GROMACS software for MD simulations and I am trying to understand the calculation of viscosity using combinations of different ensembles and different methods. For a non-equilibrium MD ...
Kavya Mrudula's user avatar
7 votes
1 answer
176 views

Can replacing some of the atoms in a covalent network with that of the element one atomic number higher make it nonstick? [closed]

I originally made the title the question I had that is a more suitable question but then it ended up too long. I had the idea that if you replace some of the atoms in a covalent network with the atom ...
Timothy's user avatar
  • 479
6 votes
3 answers
3k views

Difference between "electrical" and "electronic"?

I found that people often measure "electrical conductivity", but some may say "electronic conductivity". Can anyone explain the terms "electrical" and "electronic&...
Binh Thien's user avatar
  • 2,095
6 votes
2 answers
105 views

Books and online resources to get me started in the finite element method (FEM)

In a course on the mechanical properties of materials, I have been asked to do a paper on the "Finite Element Method" to improve my current grade. However, most of the resources I find on ...
Carlos's user avatar
  • 461
6 votes
1 answer
329 views

Software for Molecular Dynamics in Material Science

I would like to know available software that can do Molecular Dynamics (MD) simulations for any type of system, specifically inorganic and organic ones. The must cited MD packages (GROMACS, AMBER, ...
Camps's user avatar
  • 23.3k
6 votes
1 answer
137 views

About LaCrO3 space group stability

I found two space groups of $\ce{LaCrO3}$ material Pnma and Pm-3m. If someone is familiar with this material, please help to understand which phase is more stable. what are the factors that determine ...
poonam sharma's user avatar
6 votes
2 answers
217 views

Are there tools to calculate the electrical conductivity of large (>1000 atom) nanostructures?

Are there any free to use tools which can be used to calculate the electrical conductivity of nanostructured materials. The systems that I am interested in consist of several thousand atoms, and ...
PBH's user avatar
  • 2,653
6 votes
1 answer
126 views

Why does twinning take place in high rate of shock loading and low temperature?

To quote from a good textbook, which I don't remember: "Twins which are produced by mechanical deformation are called mechanical twins. Mechanical twins are produced in bcc or hcp metals under ...
user586228's user avatar
6 votes
1 answer
75 views

Where is this extra plane coming from?

Why are there solid lines drawn connecting the solid circles after twinning has taken place? Ideally, that explains a real plane, isn't it? But why are we going to get a plane out of nothing if we ...
user586228's user avatar
6 votes
1 answer
108 views

How can I calculate the elastic properties of a unit cell and a supercell?

Can someone please share with me a method to compute the elastic constants of the unit cell and doped supercell of a material? In my calculation I use Quantum ESPRESSO. And I already tried Thermo_pw, ...
Camilla's user avatar
  • 2,129
6 votes
1 answer
318 views

What is the difference between elastic and mechanical properties of materials?

I have seen many articles[1] that write in the title "mechanical properties of ...", but in the subsections of the paper, they write "elastic properties" and discuss elastic ...
Chi Kou's user avatar
  • 5,833
6 votes
1 answer
577 views

Cohesive energy of Cu with Quantum Espresso

Using this input Cu FCC vc-relax method error to calculate Ebulk, I'm trying to calculate the cohesive energy of solid Cu (Ecoh = Eatom − Ebulk). For the Eatom I'm using a similar input but with ' <...
ziulfer's user avatar
  • 231
6 votes
1 answer
62 views

How to understand effect of increase in band gap generated away from Fermi energy on conductivity?

An example would be that when we dope Nitrogen in graphene its conductivity decreases. This can be explained through other means. But can this be explained through the change in its band structure?
Ashique Lal's user avatar
  • 1,621
6 votes
0 answers
127 views

Analytical derivative method in ab initio molecular properties calculations [closed]

In order to relate results from quantum chemical calculations to experiment, it is essential to compute quantities that are directly available from measurements. Properties describe the "response&...
Sergio's user avatar
  • 357
6 votes
0 answers
81 views

Predicting the band gap or some other properties of materials before running any calculations [closed]

Can we somehow predict what sort of modulation doping will do to a material without actually running any calculations? For instance, could we use the already known density of states (DOS) of Zn to ...
Parmeet Singh EP 066's user avatar
6 votes
0 answers
49 views

Compute bulk electrical conducitivity from single-crystal measurements [closed]

If I have single-crystal measurements of electrical conductivity along 3D axes (considering for example anisotropic materials), is there any straightforward way to compute the bulk (global) electrical ...
James Arten's user avatar
6 votes
0 answers
69 views

Value of density of state effective mass and transport effective mass to calculate conductivity [closed]

How can density of state effective mass and transport effective mass can be defined to calculate conductivity for a cubic system with parabolic but anisotropic dispersion relation? What will be the ...
Shalini's user avatar
  • 1,605
6 votes
0 answers
43 views

Is it possible to calculate the variation of magnetization M(T) for a diluted magnetic semiconductor? [closed]

Is there any simulation program (for example a DFT package) to determine the variation of magnetization M(T) for dilute magnetic semiconductors or doped semiconductors with different concentrations of ...
ismail benaicha's user avatar
5 votes
2 answers
138 views

Is there a material where the conductivity drops when the current increases?

I would like to know if anyone knows of a material where the conductivity drops when the current increases? Usually, it's the opposite.
henry's user avatar
  • 161
5 votes
1 answer
340 views

How to calculate lattice parameter?

After 'vc-relax' calculation I got the cell parameters in the picture bellow. I want to mention that my ibrav=1. I think the optimized lattice parameter in this case is A=11.44879234*1.006676454 .But ...
Camilla's user avatar
  • 2,129