How to resolve "the structure is mechanically unstable" in DFT calculation of elastic property?

28 September 2022 1 5K Report

I calculated elastic properties by using DFT calculation and VASPKIT. The structure is a Ti8N6 monoclinic structue with vacancies. However, the fitting results indicate that " the structure is mechanically unstable". Why is this? How can I fix this issue?

Philip James Hasnip

It sounds like you may not have optimised your crystal structure first. I recommend adding a small random perturbation to the cell vectors and positions (to break any symmetries) and then doing a full variable-cell geometry optimisation.

Badges
Science topic

More Calvin Cui's questions See All

Do you think can be any Uranium bearing rocks in Eastern part of Iran and western part of Afghanistan?

I want to know more about Uranium ore deposits in world.

11 August 2024 6,720 0 View

Do you think can be any diamond bearing rocks in Eastern part of Iran and western part of Afghanistan?

I want to know more about diamond ore deposits in world.

11 August 2024 2,167 1 View

What is the difference between mathematical R^4 space and physical 4D unit space?

We assume that the difference is huge and that it is not possible to compare the two spaces. The R^4 mathematical space considers time as an external controller and the space itself is immobile in...

10 August 2024 6,678 14 View

If Banks do not provide credit facility, what are the options available for FPOs and impact on producer’s income?

10 August 2024 8,198 5 View

Controlling for pupil light reflex when analyzing pupil size time course?

I used eye tracking to examine how participants from two different populations (A and B) react to an image. Participants in population A exhibit larger pupil sizes over time, but they also have...

10 August 2024 3,229 0 View

What are a “Farmers Producer Organization” (FPO) and its essential features?

10 August 2024 477 5 View

Strugglling with m6A dot blot any suugesstion ?

I have been doing the m6A dot blot for a while with no improvement, I am extracting the RNA, and I can see the dots although the three biological replicas give a different reading on the memberan...

10 August 2024 8,539 5 View

Do interactions between biosphere, carbon cycle, & water cycle impact global warming & interaction between atmosphere & hydrosphere?

How do interactions between the biosphere, the carbon cycle, and the water cycle impact global warming and interaction between the atmosphere and the hydrosphere?

09 August 2024 3,291 2 View

How to get moment output in Abaqus Standart?

I have input a moment load in module load Abaqus, i put my moment load on the node surface (using reference point). I have define moment in history output and make a set for moment too. But the...

08 August 2024 4,831 4 View

How is energy cycled through the Earth's climate system and how do matter cycle and energy flow through the rock cycle?

08 August 2024 8,162 0 View

How to define an anisotropic material with asymmetric elastic compliance/stiffness matrix in ANSYS APDL?

I need to model an anisotropic material in which the Poisson's ratio ν_12 ≠ ν_21 and so on. Therefore, the elastic compliance matrix wouldn't be a symmetric one. In ANSYS APDL, for TB,ANEL...

09 August 2024 5,048 2 View

Is it possible to plot the atom-projected band structure using GPAW?

Hi, I'm currently working on a project where I need to plot the atom-projected band structure using GPAW. I've been able to calculate the band structure for my material, but I'm having trouble...

07 August 2024 269 3 View

Does continues partial charging/discharging do any harm to the BESS performance and degradation?

For a grid connected BESS (lets say 100 MW/200 MWh system, LFP battery), if we charge the BESS in such a way that whenever we can access power from the solar that will charge the BESS. Hence it...

01 August 2024 9,903 7 View

How to Post-fix Mice pup's brains?

I need to Postfix mice brains. I slice the brains using microtome at 40 microns. These are Postnatal days 7, 11, 14, and 21. I am using half the brain for other analysis, so I need to fresh freeze...

31 July 2024 1,123 4 View

Why Orca calculations take too loong?

Hello! I am trying to calculate the sumatriptan molecule, but it has been counting for five days and it does not stop. It seems to me that it is too long and I am doing something wrong. Please...

25 July 2024 3,364 5 View

Can we eliminate the stress singularity at the tip of the crack by manipulating the elastic constants?

The aim of the research here is to prevent the propagation of the crack in the fabricated elastic medium with useful applications.

25 July 2024 9,976 3 View

I am trying to find phonon, and when i run calculations, there is error ?

how to fix this error, from phq_readin : error # 1 DFPT with the Blochl correction is not implemented I am attaching my ph.in file.

23 July 2024 4,649 2 View

MDCI module in Orca software?

Dear Researchers, My question is associated with the "MDCI" method in Orca. Please let me clarify my question using a simple example: Suppose we are going to perform CBS extrapolation using "!...

21 July 2024 1,632 0 View

How to fix install package meta in R?

> library(meta) Error: package or namespace load failed for ‘meta’ in loadNamespace(i, c(lib.loc, .libPaths()), versionCheck = vI[[i]]): there is no package called ‘numDeriv’

18 July 2024 3,536 0 View

GIS (How can i fix when it appear in mines despite selecting WGSWGS 84 / UTM zone 38N?

I have a problem with geo-referencing a shape file. How can I fix it when it appears in mines despite selecting WGSWGS 84 / UTM zone 38N?

18 July 2024 2,696 1 View