[Pw_forum] keep getting negative frequencies in phonon calculation

Dear Researchers, I think this is an old problem, but I require your advice about how to solve this problem. I am trying to calculate the phonon dispersion curve of a 2D insulator material, and followed example 02 of phonon program. In the ph.x input file I have used: tr2_ph=1.0d-12,

Re: [Pw_forum] keep getting negative frequencies in phonon calculation

I have encountered such a problem for my studies. Taking care of following points may help you: 1- see the stress and pressure for your crystal. its force should be very low. 2- use large cutoff for wfn and rho, even much larger than the converged values against energy/atom or force/atom

Re: [Pw_forum] keep getting negative frequencies in phonon calculation

Dear Sir, Thank you very much for your kind help. Khalid Ibne Masood M.Sc student BUET On Sat, Aug 8, 2015 at 2:04 PM, David Foster wrote: > I have encountered such a problem for my studies. Taking care of following > points may help you: > > 1- see the stress

Re: [Pw_forum] error: tcp_peer_recv_connect_ack

Dear Mahya I agree with Axel, too. But some points for you: 1- The first thing, you should recognize your crystal symmetry, and choose proper ibrav 2- start the input file from PW examples, and change the commands according your need. 3- Always, I emphasize, always, check your input file with

[Pw_forum] charge density

I calculated the charge density difference plot using VESTA for understanding the bonding mechanism between adsorbent and adsorbate. The system I used here is Li adsorbed on carbon based substrate and it was shown in the figure. Yellow and Blue colors are represents the positive and negative

[Pw_forum] Cp

Dear developers Why rescaling does not work for cell temperature in cp while it is introduced as a permitted parameter? Kind regards Ashkan Shekaari Tell: +98 933 459 7122; +98 921 346 7384 ___ Pw_forum mailing list Pw_forum@pwscf.org

[Pw_forum] Dielectric constant of Monolyer MoS2 in .ph

Dear researchers Is it possible to calculate static dielectric constant of mono/bi layer MoS2 using .ph package in quantum espresso? I have performed self consistent formulation already and have been using the following code for .ph package found in a tutorial: tr2_ph=1.0d-14,

Re: [Pw_forum] Dielectric constant of Monolyer MoS2 in .ph

Dear Kanak Datta if the system is considered metalic, it gives a error like "no elec. field with metals". Please do calculation in non-metalic condition. regards 2015-08-08 23:48 GMT+03:00 Kanak Datta : > Dear researchers > > Is it possible to calculate static dielectric