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 (+...

25 July 2018 4,045 6 View

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

17 December 2015 6,112 7 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 4,881 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 5,291 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 9,398 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 2,452 3 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 6,500 2 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 9,376 3 View

How to calculate radial distribution function (RDF) of a complex from Ab initio MD simulation trajectory?

Hi all, Is there any software or webserver to read the molecular dynamics (MD) simulation trajectory which obtained from Ab initio MD simulation to calculate the atom-atom radial distribution...

25 January 2021 9,474 3 View

Why it is required to optimize a unit cell generated from cif lattice parameters and atomic coordinates during ab initio solid state calculations?

A cif file represents a unit cell with minimum energy. My question is, in the start of any ab initio calculation for unit cell generated from the cif file, why we are advised to optimize cell...

19 January 2021 9,883 3 View

How to calculate IR and RAMAN spectra form Born charge ?

I am using crystal 17 for my solid state ab initio calculations. For some reason the program is not able to produce the Raman spectra but have generated born charges. Is there any way to produce...

11 January 2021 2,317 2 View

How can we choose the right method for Gaussian calculations?

I'm not working on biomolecules, I work on Organic, Organometallic, and sometimes inorganic structures. Do you know a simple way to apply the right calculation method? Is there any article or...

10 December 2020 3,396 5 View

How can one calculate Gibbs energy and entropy in ab initio molecules dynamics?

Hello, I've been investigating a bunch of monomers which spontaneously react in water to form a polymer. I would like to know how to calculate the thermodynamics of such a system. On the surface,...

18 November 2020 5,595 3 View

Physical significance of Gap between optical and acosutic branches in Phonon Dispersion?

Hello Everyone, Recently I am doing some Phonon branchesbased studies. For some materials the gap between the optical and acoustic branch is small, for some it's large and for some there is no...

04 November 2020 3,987 2 View

Can someone help me with the error in crystal17 output ?

I am a new user to crystal 17 (https://www.crystal.unito.it/index.php). I was trying to optimize a molecule using crystal17 but it is throwing following error: "ERROR **** INPUT3 **** n-D...

19 October 2020 5,211 2 View

Is there a way to make Facio (GUI for FMO) work on Mac OS Catalina?

I am trying to use the FMO (Fragment Molecular Orbital) method which works to make large (thousands of atoms) molecules more palatable for ab initio computational quantum-chemical calculations on...

29 September 2020 4,896 2 View

Can you suggest any book to learn material simulation via density functional theory?

I am new to material simulation and I am willing to learn the theoretical aspects like what is k point mesh, how to interpret band diagram, how born charge results in IR spectra etc. I have...

29 August 2020 1,173 8 View

Transmembrane Protein 3-D Coordinate File Preparation Question?

Hello I hope you are all doing well.:) Several transmembrane Pannexin1 3-D coordinate files have been submitted to the PDB, however, I believe all are missing coordinates in some of the Pannexin1...

11 August 2020 4,875 3 View