[Pw_forum] tot_charge in nano structures

Dear all, Thanks for reading it. I would like to add some charge to graphene layer by adding tot_charge in SYSTEM window. My problem is energy convergence versus vacuum, it isn't converge even at high vacuum (~30Ang and more), is there any trick to solve this problem? Thank you, Zara

Re: [Pw_forum] QE-GPU (installation)

Here I am attaching my SERVER architecture and GPU device enquiry (text file) After whole long day I found some reasons (I don't know whether they are correct or not ): Initially I written my GPU was Tesla K40, but it is not. Actual series name was *NVIDIA Tesla K40m. *Sorry for that, that was

Re: [Pw_forum] QE-GPU (installation)

On Dec 5, 2016, at 2:11 PM, Phanikumar Pentyala wrote: > After change the compilation command: ./configure --enable-parallel > --enable-openmp --with-scalapack --enable-cuda --with-gpu-arch=sm_35 > --with-cuda-dir=/usr/local/cuda-8.0/bin --without-magma --with-phigemm

Re: [Pw_forum] QE-GPU (installation)

Thank you for quick reply So I downloaded QE-GPU version 5.4 and updated my CUDA version to 8.0. After change the compilation command: *./configure --enable-parallel --enable-openmp --with-scalapack --enable-cuda --with-gpu-arch=sm_35 --with-cuda-dir=/usr/local/cuda-8.0/bin --without-magma

Re: [Pw_forum] Negative Phonon Frequencies - Numerical instability or unstable structure

Sorry forgot half of the answer acustic branches should be flat along k_z direction, I would check that is so. If it is not so, maybe you are adding non physical interactions between periodic images and this can cause the numerical instabilities. I don't know whether your program is able

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Re: [Pw_forum] Negative Phonon Frequencies - Numerical instability or unstable structure

Respected Sir. I have computed the force for the super cell and used the parameter --dim="2 2 1" . Regards, Ghadiyali Mohammed Kader Research Scholar University of Mumbai. ___ Pw_forum mailing list Pw_forum@pwscf.org

Re: [Pw_forum] QE-GPU (installation)

Dear Phanikumar, upgrade to QE v5.4 and upgrade to the latest QE-GPU from GIT (https://github.com/fspiga/QE-GPU/archive/5.4.tar.gz). I've just create a tag to simplify checkout operations). Moreover you want to use MAGMA if you do not use ScaLAPACK. if you disable both, most likely you will

Re: [Pw_forum] Negative Phonon Frequencies - Numerical instability or unstable structure

Then one of the 3 acustic branches ( probably the one you gave problems with ) should be flat. I don't know how this phononpy works, maybe there is a way to deal directly with 2D systems, otherwise just find a way to set to 0 all the interatomic force constants that correspond to

Re: [Pw_forum] Negative Phonon Frequencies - Numerical instability or unstable structure

Dear Mohammed, Have you computed your force constants for a supercell or are you inter/extrapolating q≠Gamma from the --dim=“1 1 1” force constants? If it’s 1 1 1, try to make a supercell that will give you access to the zone-boundary points so that your interpolation becomes better. Best

Re: [Pw_forum] Negative Phonon Frequencies - Numerical instability or unstable structure

Hi, The structure is two dimensional similar to bi-layer graphene. Regards, Ghadiyali Mohammed Kader Research Scholar University of Mumbai. ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum

Re: [Pw_forum] Negative Phonon Frequencies - Numerical instability or unstable structure

Hello Mohammed If the phonon were computed with phononpy for any numerical problem maybe you will find more help in the forum of phononpy users. Could you provide more information about the structure ? Is it 3D or 2D ? greetings - pietro On 05/12/2016 08:23, Mohammed Ghadiyali wrote: