[QE-users] 回复: 回复: Is it necessary to do "vc-relax" with pw.x before doing CPMD with cp.x ?

Dear Hsin-Yu, Thanks a lot for your explanation and sharing the document. Now I understand the two questions much better, but I have two more questions to consult with you. The first is a small question: In the CPMD tutorial, it also suggests to tune ‘emass_cutoff’. What is the physical

Re: [QE-users] 回复: Is it necessary to do "vc-relax" with pw.x before doing CPMD with cp.x ?

Dear Kejiang, Good questions! The physical idea of emass is to slow down the timescale of the fictitious electronic motions (to allow larger integration timestep, dt, for propagating CPMD). However, emass has to be chosen to maintain good adiabatic separation between fictitious electronic and

[QE-users] 回复: Is it necessary to do "vc-relax" with pw.x before doing CPMD with cp.x ?

Dear Hsin-Yu, Thanks a lot for your explanation and suggestion. As per your comments, it might be due to high emass since I used the default emass (400). I will try to decrease emass (300, 200, 100) to see whether the force can converge. Regarding ‘emass’, I have one more question: Is it a

Re: [QE-users] Is it necessary to do "vc-relax" with pw.x before doing CPMD with cp.x ?

Hi Kejiang, Structural relaxation in cp.x (step 2 as you mentioned) can involve the cell degrees of freedom (in addition to the ionic ones) and thus is in principle equivalent to doing "vc-relax" in pw.x. As such, it is unnecessary to do a "vc-relax" with pw.x. In practice, proper parameter

Re: [QE-users] Regarding band gap error

Dear User (please sign always with name and affiliation your posts) 1) The usefulness of our replies is proportional to the details in your post, which are scarce. 2) We can help you if something goes wrong in the calculation. It is much more difficult that we know the physics of your

[QE-users] Regarding band gap error

Dear Users I have been trying to calculate the properties of a heterojunction consisting of a cubic and wurtzite structure along Z-direction.Instead applying proper vacuum of around 20 angstrom I don't get any band gap. After relaxation the structure is losing its symmetry. Please suggest to me

[QE-users] projwfc -> MOs ?

Hello QE users, The documentation for projwfc indicates that that QE wavefunctions may be projected onto GTOs for the purposes of construction of, e.g. Lowdin charges. Can the 'MOs' generated therein be output as, say, a MOLDEN-format file containing the equivalent GTOs? Thanks, Steven

[QE-users] Is it necessary to do "vc-relax" with pw.x before doing CPMD with cp.x ?

Dear QE-Users, I am doing CPMD with cp.x for iron oxide system following the official tutorial which introduced two steps (Step1: Reaching the electronic ground state; Step 2: Relax the system) before doing cpmd. However, in both the electronic minimization and ionic minimization processes, I