Hitanshu Sachania

17 Questions 32 Answers 0 Followers

Questions related from Hitanshu Sachania

[VASP] Are k pts, ECUT, and sigma convergence required for SQS or can we use the same values as those for a corresponding ordered cell?

Considering that the bonding environment or the chemical arrangement within the ordered cell and SQS are different.

18 November 2019 9,739 10 View

ISTART and VASP?

The manual for VASP recommends using ISTART = 1 for calculations wherein the cell shape/volume changes, but it recommends ISTART = 2 for the same scenario as well. A little clarification (+...

26 July 2018 4,434 6 View

Smearing and VASP?

The manual page about ISMEAR is a bit cursory. It's difficult to understand which method to use and when. Can you help me understand it with examples (like Au, CuO, etc.)?

26 July 2018 6,149 4 View

Is there an optimum number of k points in the irreducible Brilloiun zone that is necessary for good calculations of bulk total energy?

I'm using a genetic algorithm based global optimisation package, USPEX, to search stable structures of non-stoichiometric transition metal compounds. The code has a limitation - we aren't able to...

11 July 2018 7,455 12 View

USPEX - Running the code?

I have a few embarrassingly basic questions about USPEX and job submission. Here goes... What are USPEX and USPEX.m. What is the difference between them? Where and how does the code make use of...

25 February 2018 7,323 2 View

Can the mass ratio of electron to proton (nucleus) change w.r.t. change in temperature, for an H atom?

The ratio is ideally ~1 : 1836. At what temperature does it fall to 1 : 1800?

26 September 2017 1,002 3 View

In the synthesis of nanoparticles by the coprecipitation method, particles precipitate and are vividly visible. How can we actually see nanoparticles?

Shouldn't nanoparticles be invisible to the naked eye? There is some color the clear liquid retains. Is it because there are some nanoparticles in there imparting this color and the precipitate...

18 December 2015 6,269 7 View

Quantify/visualize atomic clusters in multi-component crystalline materials

Let's say we have a material AB. Is it possible to detect atomic clusters of A atoms experimentally? The size of clusters in question: 2 atoms (nearest neighbour pairs), 3 atoms (nn triangles), 4...

01 January 1970 2,622 3 View

[Resolved] Are nearest neighbours always equidistant from the lattice point in question?

Consider an FCC structure. Are all the 1st nearest neighbours (NN) always at a distance of lattice parameter/sqrt(2)? What about disordered random solid solutions?

01 January 1970 9,534 3 View

[VASP] Relaxation in Steps.

Is it alright if I run an ISIF = 3 and ISPIN = 2 calculation for 2 hours, after which the job terminates (limited computing resources), and then simply copy the CONTCAR to POSCAR and start it...

01 January 1970 5,456 7 View

Does electronic magnetic moment affect the phonon band structure or density of states?

I wish to do DFT calculations and use the frozen phonon approach via Phonopy. Should I pay attention to the magnetic moments? Sometimes, individual atoms in a crystal have different magnetic...

01 January 1970 9,537 7 View

Acoustic Phonon Modes & Heat Capacity

I read in Ashcroft and Mermin's Solid State Physics how only those modes that have a frequency tending to 0 as k(or q) tends to 0 contribute to specific heat capacity. This would include the 3...

01 January 1970 6,683 2 View

[Solved] Unit Consistence for Vibrational Entropy in Dr Brent Fultz Review on Vibrational Thermodynamics of Materials

Please find the review attached with this message. Eq 84 (along with preceding equations) establish a formula for vibrational entropy but I can't seem to confirm the consistency of units. Please...

01 January 1970 5,041 3 View

Steps to generate the Density of States plot using VASP?

I understand I first need a properly converged system - check. Now, I need to calculate a self-consistent charge density (CHGCAR). Later I have to do a calculation with IBRION = -1, NSW =0, need...

01 January 1970 2,993 5 View

How to calculate correlations for a disordered state in mcsqs?

The paper, "Effective Stochastic Generation of SQS" is a bit vague about it. Please help me understand it.

01 January 1970 687 1 View

Why do we take a big supercell while generating displacements in PHONOPY?

When using the DIM tag we give a size for the supercell. Why do we do that? Isn't the VASP (DFT) relaxed cell itself a supercell. Let's say I generate a large randomized special quasi-random...

01 January 1970 1,412 2 View

Why does the DOSCAR file have multiple entries for DoS?

Please look at the attached DOSCAR file. It is from an lm decomposed DoS calculation. First it lists the DoS and integrated DoS between EMAX and EMIN. Next it lists lm decomposed DoS for NEDOS...

01 January 1970 4,081 3 View