Topics

16

General Questions and Answers / BZ Routes: K and K-prime

« on: March 15, 2016, 21:25 »

When using the VASP Scripter, how can you specify K-prime (as opposed to K).  I need a K-Gamma-K' because my k-space is strained, and won't be symmetric; so I get K'.  Do I do something like the following in the KPOINTS file?

0.333333 0.333333 0.000000 ! K
0.000000 0.000000 0.000000 ! G

0.000000 0.000000 0.000000 ! G
-0.333333 -0.333333 0.000000 ! K

Thanks,
Mark

17

General Questions and Answers / Documentation for VASPPlugins?

« on: March 2, 2016, 18:39 »

I attempted to find documentation for the VASPPlugin python commands, but was unable to locate them on the QuantumWise website.  Can someone point me in the right direction?

Thanks,
Mark

18

General Questions and Answers / Band Gap calculation without ATK

« on: March 1, 2016, 08:04 »

I can successfully create and view a bandstructure using VNL.  But how can I determine the band gap (direct and indirect) and Fermi level?   I get the impression their are scripts for this, but they require ATK.  Is there an alternative way of finding the band gap?

Mark

19

General Questions and Answers / Pov-ray for Dummies?

« on: February 2, 2016, 20:57 »

I'm looking to create professional quality images of charge transfer density plots.  What is the easiest method of generating publication-level images from chgcar data?  A commercial application is acceptable.   I can generate .pov files with VNL correctly.  I'd prefer something user-friendly.  Installing and using pov-ray has been unpleasant.   

Thanks,
Mark

20

General Questions and Answers / EIGENVAL files and BandStructure Analyzer

« on: January 6, 2016, 03:32 »

I'm attempting to use the Bandstructure Analyzer on a set of VASP files.  Although the eigenval file shows up in the Project File list, the Labfloor does not include eigenval, so the Analyzer option is disabled.   My eigenval file appears valid.   Any suggestions?   Doscar correctly shows the DOS, and chgcar provides a 2-D View.

Thanks,
Mark

21

General Questions and Answers / POSCAR: Import-Export Issues

« on: December 31, 2015, 21:23 »

I'm experiencing a really odd problem with importing/exporting poscar files with vasp.  Attached are two files: a good, working poscar before importing into VNL, and another one that is exported from VNL.  I made no changes during the export.

The exported version is unusable.  First of all, the atoms are set to fixed positions (which I didn't specify), and if delete the "T" option so they can relax, the vasp run crashes with errors that don't make any sense.  The "before" version works perfectly fine.  But the "after" version does not run on vasp.  I'm using the same INCAR and KPOINTS for both vasp runs.

I don't understand how to fix this behavior.  Any suggestions would be appreciated.

Thanks,
Mark

22

General Questions and Answers / Charge Density Plots

« on: December 7, 2015, 00:45 »

How can I create charge density plots using VNL?  I can do using VESTA (as shown), but not sure what the steps are in VNL.  I looked through the tutorials and videos, and didn't see any examples.

Mark

23

General Questions and Answers / 1T'-MoS2 lattice structure

« on: December 6, 2015, 06:16 »

Is there an "open-source" cif or poscar model for 1T'-MoS2?  2H and 1T are easy to come by, but since 1T' is a distorted structure, I'm not clear how to create this from scratch.

Mark

24

General Questions and Answers / WS2: hexagonal vs triclinic

« on: November 20, 2015, 05:57 »

For WS2, the VNL database uses a Hexagonal lattice.  I imported a CIF, and it's Triclinic.  I suppose they are equivalent, depending on how you define your unit cell, but which is the "real" stucture?  I wasn't aware of two different representations, so I will need to be careful and use one or the other.  But is one more common?

Thanks,
Mark

25

General Questions and Answers / Changes to POSCAR

« on: November 14, 2015, 22:15 »

I import a known, good WS2 POSCAR file (see the attached POSCAR-GOOD).   When I export this file I get the other attached file (POSCAR-GOOD-VNL).  However, the lattice parameters have changed.  A VASP run works OK on the POSCAR-GOOD file, but crashes on the POSCAR-GOOD-VNL file. 

How do I prevent VNL from modifying the poscar?   Or how do I make VASP work with the exported POSCAR-GOOD-VNL version?  Still learning how to use VNL!

Thanks,
Mark

26

General Questions and Answers / Animated GIF not working in Movie Tool

« on: November 8, 2015, 17:17 »

In Movie Tool, I right-click on the image, choose "Export Animated GIF", choose a file name, and press OK, but no file is generated.  A message appears on image "generating movie -- please wait".  But nothing happens.   VNL still runs OK.   

I have the Demo version of VNL 2015.rc2.  Is creating the animated GIF disabled?  I'm running Ubuntu 14.04.

Mark

27

General Questions and Answers / MoS2 2H-1T NEB transition

« on: November 5, 2015, 22:14 »

I successfully worked through the Platinum NEB tutorial, and want to apply NEB to a MoS2 2H-1T transition.  I can do this using ase-python, but unclear how to configure the 2H and 1T slabs using VNL.  Any suggestions?  I'm still learning how to use VNL after having worked with ase-python.

Thanks,
Mark

28

Scripts, Tutorials and Applications / NEB and Vasp

« on: November 4, 2015, 23:39 »

I have successfully  run the Platinum NEB tutorial, but it uses a local calculator, rather than generating vasp files.  Is there a way to re-direct the Job Manager to produce vasp files? 

Thanks,
Mark

29

Scripts, Tutorials and Applications / MoS2 Nanotube

« on: November 3, 2015, 21:27 »

I'm following the MoS2 Nanotube tutorial, but I've been unable to duplicate the nanotube.  I've read other helpful posts regarding this topic.  I'm using 2015.rc2.

I use the improved transformation, swap x <=> y, repeat A=20, and replicate the video up to time-frame at 2:58.

However, what happens between 2:58 and 2:59??  A significant unexplained transform takes place.  What is needed to make the cell look like 2:59?

Thanks,
Mark