ABINIT Discussion Forums

Warnings and Comments are there for you to read and determine if they matter to your calculation. It is up to the user to decide of the comment/warning is critical to the outcome of your calculation. For example, you can get a warning when your calculation reached the nsf (during relaxation) without...

What happens when you try the following command?

Hello houssem, Since you already relaxed your structure, you should start your calculation using the input file "telastic_2.in" in the tutorial. Once you replace the system dependent variables (rprim, acell, etc. ) the input file will work for the first step of the calculation. As I am sure you noti...

Hello Hameed!

You can start by looking at the tutorial for the optical properties found at https://docs.abinit.org/tutorial/optic/.

There are example input files given in the tutorial that should be able to help you out.

-Nick

Hello Yang, The Fermi energy is determined by "counting" the number of electrons in the unit cell. You can think of this as integration of the density of states from negative infinity to some energy Ef such that the result of the integral is the number of electrons in the unit cell. Thus, ...

Hello domakani,

I suggest you look at https://docs.abinit.org/variables/gstate/#ratsph which provides two physically motivated ways to determine this variable.

-Nick

Hello, natsph is a number corresponding to the number of atoms that you want an atomic projected density of states for. I would personally just do all atoms in your unit cell. iatsph is the index of the atoms you want in the atomic projection of the density of states for. ratsph is automatic if you ...

Hello, The variable shiftk is used to shift the k-point grid by a fixed amount after Abinit determines the list of irreducible k-points. For most calculations, one can safely set shiftk = 0 0 0 and nshiftk = 0. See https://docs.abinit.org/variables/basic/#shiftk for additional information and some e...

Hello Domakani, I understand your point. I also like to have an example of my own when I am learning about a new code or method. As I mentioned in my post, some of the variables you will need to modify are ntypat, znucl, natom, xred, typat, etc. You can find more information about each of these inpu...

Hello Hola,

As we release new versions of ABINIT it is possible that the requirements on input variables change. The various help menus and variable documentation always corresponds to the most recent release of ABINIT.

-Nick

Hello Theldaelis and Jacek, There is currently no way of directly printing the momentum matrix elements. As Jacek pointed out, you can calculate them with ABINIT and OPTIC (see the optics tutorial toptics_1.in where the wave functions and the perturbed wave functions are calculated). OPTIC then read...

Hello Sbphys,

How are you generating the k-point mesh. Could you provide the input file?

Thanks!

Hello Domakani! There are a few changes that are needed to the input file. The one you attached is for a crystalline solid (Silicon in fact). To change this for AlP you would need to modify several of the input variables. Some of the variables that you need to modify are: ntypat, znucl, natom, xred,...

Hello hameed1987,

You can use Abinit to study Heusler compounds. To determine how to use abinit and what properties can be calculated I direct you to the abinit tutorials page https://docs.abinit.org/tutorial/

Have a great day!

-Nick

Hello hameed1987, As indicated in the warning message, the tab character is found in AT LEAST one place in your input file. The input reader for Abinit does not understand tabs. Therefore, they should be removed from your file. In this case, I found 8 tab characters! The fixed lines should be (lines...

Hello sbphys.

Could you please post the input file for your calculation?

-Nick

Hello Monia, You will need to generate a supercell which contains the two parts you want. I suggest using the Atomic Simulation Environment found at https://wiki.fysik.dtu.dk/ase/ . This is a python based program that will allow you to first create the two structures that you want with the symmetry ...

Hello Rita Maji,

The conversion between xcart and xred involves the matrix rprim. See https://docs.abinit.org/variables/basic/#xred for a simple example.

-Nick

Hello Hola! You are correct that it is the sqrt(3)/2 that leads to the Abinit error message. As it states in the tutorials, the input reader of Abinit can read some fractions (1/2, 1/3, etc) but cannot read in anything more complex such as the sqrt(). I suggest replacing sqrt(3)/2 by 0.86602540378 (...

Hello Shalom, Looking at tgw1_1.in and comparing it to your outfile I have noticed one important difference. The infile tgw1_1.in is for fcc Si and your outfile is for fcc Al which may explain all the differences you are observing. I suggest checking your input file znucl should be set to 14 (Si) an...

Hello Narges, In my experience, this is most likely a problem with the number of digits used for xred since the symmetry finder has a rather high precision. I suggest rebuilding your super-cell from a unit cell that contains more digits for the atomic positions (xred) with around 8 relevant decimal ...

Hello Ogundare, It is good to see that you want to start running and using Abinit. For a detailed guide on running calculations in Abinit I suggest you read the Abinit tutorials . These tutorials are specifically designed to guide you through the process of running calculations on Abinit. If you hav...

Hello Loukai, Welcome to the Abinit Forums! While I do not know the answer to your question I do believe that your question is in the wrong sub-form. The correct place for this question is in the "Platform specific questions" sub-form where your post would receive more attention. -Nick

Hello NimblePanda, During any DFT calculation, for any system you wish to investigate, you need to first determine the energy cutoff (Ecut) and k-point mesh for your particular system. As you have shown in your example, you are currently running 13 calculations, starting from an ecut of 10 Hartree a...

Hello again, I am glad to read that things are working for you now. To clarify: Your original code was acell 8.2 8.2 15.0 Angstrom And Abinit had a problem with the number of decimal places you used. The corrected input file should have acell 8.200000 8.200000 15.00000 Angstrom Does that help clear ...