Unanswered Questions
231 questions with no upvoted or accepted answers
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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 ...
- 453
9
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Different Results obtained while doing multiple runs from same inputs in VASP
I have been trying to optimize the parallelization parameters in VASP. By varying the parameters(such as KPAR and NCORE) I am trying to reduce the Elapsed time that is printed at the end of each line. ...
- 1,701
9
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118
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DIY molecular dynamics for Xenes on crystal surfaces; where can I get applicable open-source force field parameters that I can use in my scripts?
The linked question(s) below describes a DIY project to simulate how Xenes (honeycomb nets of atoms like graphehe) behave on single crystal surfaces. Behaviors include rotation, strain, and heigh ...
- 2,074
8
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258
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Contribution in action from collisions for a gas?
So if I write the action for a gas:
$$ S = \int (T -U) dt \tag{1}$$
where $T$ is the kinetic energy and $U$ is potential energy.
I suspect there is a constant term (which does not affect the equations ...
8
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How to calculate small and wide-angle X-ray scattering spectra for the hydration shell restricted by a distance radius criteria
My main aim is to extract the SWAXS spectra for the hydration shell surrounding a solvated molecule and I am unfamiliar with the idea of excluded solvent volume. I tried looking online but many ...
- 2,362
7
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157
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Correct method for structure optimization using DFT tools
Lets's say I want to start off DFT calculations for a material whose experimental cell constants are known. So I have two ways to get the correct structure to later on calculate, say, band structure ...
- 939
7
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Question about Constructing Supercell Layers for MD Simulations for Solid-Solid Phase Transitions
I am a newcomer to MD simulations,
so my questions may be at a basic level,
but I appreciate your understanding.
I would like to simulate solid-solid phase transitions using MD simulations.
To begin ...
- 3,770
7
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175
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Is there a way to set the spin multiplicity in a VASP calculation?
I will greatly appreciate if someone can point to whether I can specify the spin multiplicity of a vasp calculation?
I am trying to get the potential energy mapping of a system with neutral slab and a ...
- 551
7
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231
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Apparent conservation of potential energy in NPT simulation?
I was examining a system with a problematic equilibration (more details given at the end, but probably unnecessary to answer the question), and came upon what is presumably a pretty basic conceptual ...
7
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176
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How to analyse structure factors calculated from a mixture of isotropic amorphous substrates
I am looking for a way to computationally analyse the interactions between two molecular species (as solute and solvent) in an isotropic mixture using X-ray scattering. Is there a guideline as to how ...
6
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116
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Spin-orbit coupling(SOC) in geometry optimisation
When I tried including SOC during the optimization of InBi lattice constants, the lattice constant increased from 4.6 Å (without SOC) to more than 6 Å (with SOC), which seems like an 'incorrect' ...
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6
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132
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Free energy calculation as a function of temperature over phase transition
I've run a molecular dynamics simulation (NVT) of a simple Lennard-Jones system of a few particles and I'm trying to calculate the Helmholtz free energy $\Delta F$ as a function of temperature over ...
- 121
6
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91
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How can we calculate transverse and longitudinal optical phonon frequencies
Could you please help me to calculate the "transverse and longitudinal optical phonon frequencies" from phonopy+vasp output files?
These parameters will help me to calculate the high-...
- 61
6
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229
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Regarding use of GCMC to add water molecules
I am working on a goethite system, and wish to fill the unit cell with water molecules for AIMD simulation using quantum espresso. For this, some papers[1],[2] indicated the use of Grand Canonical ...
6
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178
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DFT+U for RPA Ground State
For RPA calculations in VASP, a four step process can be utilized where the first step is to compute the occupied orbitals at either the GGA or hybrid GGA level.
I am curious with materials that are ...
- 11.6k