Community Digest

Top new questions this week:

In DFT codes, which energy is forces derivatives of?

There was a discussion in our research group recently, that I did not follow completely, but the crux was: In most DFT codes (especially VASP), when we compute the forces, which energy are the forces ...

density-functional-theory forcefields  
user avatar asked by ipcamit Score of 7

Number of phonons into a supercell

I am a masters student who's struggling with Quantum ESPRESSO for my thesis. I'm at the end of my internship and I think I may have done some conceptual error, which of course are linked to practical ...

quantum-espresso phonons supercell  
user avatar asked by Martino Napoli Score of 5

berry curvature Quantum espresso

I want to run berry curvature calculation using quantum espresso machine is there any method to run these calculation help me in this case.

quantum-espresso berry-phase  
user avatar asked by saba saba Score of 3

How do I fill my simulation box with molecules efficiently?

I am using VASP for DFT simulations so far and want to start with AIMD of solid liquid interfaces. Now I stand before the problem of how to fill my cell appropriately with molecules. So far I have ...

density-functional-theory vasp molecular-dynamics aimd  
user avatar asked by And Score of 3

Pseudo potential generation for XPS calculation

I want to compute the XPS spectrum for an iron oxide using pseudo potentials, and I would need some guidance in how to generate the necessary pseudo potentials. I am using a great software called APE ...

pseudopotentials  
user avatar asked by Gyorgy_hantal Score of 3
user avatar answered by Robert Lawrence Score of 1

Thermal stability of materials by first principles

I'm doing a DFT study of monolayers using Quantum espresso. I want to check the thermal stability of layers. It is quoted sometimes in experimental papers that integrity of layer is maintained at 0K-...

density-functional-theory quantum-espresso  
user avatar asked by Rafi Ullah Score of 2

Empirical approaches for predicting mass spectrums

One way of predicting a mass spectrum of a new molecule is to run a semi-empirical BOMD computation where the molecule is ionized, gets a big energy and starts dissociating. However, I suppose that in ...

quantum-chemistry  
user avatar asked by Linkey Score of 2

Greatest hits from previous weeks:

Artificial muscles and their efficiency

Most of the artificial muscles are based on either pneumatic power or nylon fibers being heated so they contract. These methods consume more energy than what can be utilized. Likewise, in early days ...

materials-engineering  
user avatar asked by gfdsal Score of 20
user avatar answered by Matt Score of 6

When should "vc-relax" be performed over "relax" calculations in Quantum ESPRESSO?

I'm new to Quantum ESPRESSO and I have read that there are several scenarios when relax calculations are preferred over vc-relax calculations, for example in maintaining vacuum while modelling surface....

density-functional-theory quantum-espresso geometry-optimization cell-optimization  
user avatar asked by Anoop A Nair Score of 13
user avatar answered by Xiaoming Wang Score of 15

How to input 3D coordinates from xyz file and connectivity from SMILES in rdkit?

I am working on a QSAR project where the 3D structural descriptors are an input to a machine learning model. I am generating the descriptors using the python Mordred API (which uses rdkit). ...

python machine-learning rdkit smiles qsar  
user avatar asked by S R Maiti Score of 11
user avatar answered by Geoff Hutchison Score of 7

How does the recent Chinese quantum supremacy claim compare with Google's?

Very recently, China claims achieving 'Quantum Supremacy' with the world's fastest Quantum Computer. Their computer was designed as a circuit of lasers, beam splitters and mirrors (see figure bellow) ...

high-performance-computing quantum-computing  
user avatar asked by Camps Score of 29
user avatar answered by Nike Dattani - No Free Time Score of 34

Is ARM64 the next big thing?

Considering how GPUs in matter modeling was first recognized in gaming devices like PlayStation, it is also interesting to consider whether ARM64 chips, which are the type of chips in modern smart ...

high-performance-computing software-recommendations soft-question  
user avatar asked by Cody Aldaz Score of 23
user avatar answered by taciteloquence Score of 27

How to obtain spin projected band structure for system with Spin Orbit Coupling?

Spin-orbit coupling[1] means the system has a non-collinear spin. Therefore, spin exists as a spinor, hence there is no meaning to 'up' and 'down' spin. Still, is there any way to get fat-band plot ...

quantum-espresso spin-orbit-coupling spin-polarization  
user avatar asked by Ashique Lal Score of 9

Inversion symmetry in 2D materials

Transition metal dichalcogenides (TMDs) are composed of three atomic planes and often two atomic species: a metal and two chalcogens. The honeycomb, hexagonal lattice has three fold symmetry and can ...

from-phys-se symmetry space-groups 2d-lattice dichalcogenides  
user avatar asked by Carmen González Score of 8
user avatar answered by Felix Score of 8

Can you answer these questions?

quantum espresso assume isolate 2D confusion

I have been playing with a PTO ferroelectric slab in vacuum with Quantum Espresso. More specifically, I wanted to understand what the assume_isolated = '2D' does. ...

quantum-espresso  
user avatar asked by lucian Score of 2

How may I get reasonable lattice constants of hybrid halide perovskite material ((BA)2PbBr4 here) using SIESTA?

I am relaxing the structures of hybrid halide perovskite material,(BA)2PbBr4 here. I tried to use GGA-PBE or LDA-PW92 exchange functionals, and pseudopotential files come from ...

density-functional-theory geometry-optimization siesta  
user avatar asked by xinbiao wang Score of 2

Default ways to compute decomposition and formation enthalpies in Siesta

I was examining the material project database and saw the thermodynamic stability section of crystalline silicon. I noticed that they compute formation and decomposition enthalpies. I wonder if there ...

siesta  
user avatar asked by Carlos Andrés del Valle Score of 2
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