CP2K Open Source Molecular Dynamics

User Tools

Site Tools

Trace:
howto:running_qe_computation

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
Next revisionBoth sides next revision
howto:running_qe_computation [2019/08/18 13:48] – [Cell relaxation] mtaillefumierhowto:running_qe_computation [2019/08/20 06:17] – [Molecular dynamics] mtaillefumier
Line 454: Line 454:
 </code> </code>
  
-===== Cell relaxation ===== +===== Molecular dynamics =====
- +
-Quantum expresso supports many types of calculations that cp2k supports natively. For instance, it is possible to do molecular dynamics in cp2k with the sirius backend, something that QE can do as well. To do this, we can start from the previous cp2k input file for Si7Ge and add a small section for setting the parameters relevant for the molecular dynamics+
  
 +Quantum expresso supports many types of calculations that cp2k supports natively. For instance, it is possible to do molecular dynamics in cp2k with the sirius backend, something that QE can do as well. To do this, we can start from the previous cp2k input file for Si7Ge and add a small section for setting the parameters relevant for the molecular dynamics. The ''symmetry'' parameter **should be off** during molecular dynamics configurations. 
 + 
 <code> <code>
 &FORCE_EVAL &FORCE_EVAL
Line 470: Line 470:
        ELECTRONIC_STRUCTURE_METHOD  pseudopotential        ELECTRONIC_STRUCTURE_METHOD  pseudopotential
        SMEARING_WIDTH 0.01        SMEARING_WIDTH 0.01
-       USE_SYMMETRY true+       USE_SYMMETRY false
        NUM_MAG_DIMS 0        NUM_MAG_DIMS 0
        GK_CUTOFF 6.0        GK_CUTOFF 6.0
Line 550: Line 550:
 </code> </code>
  
-you should obtain a file ''Si7Ge-pos-1.xyz'' that contains the positions of the atoms and ''Si7Ge-1.ener'' that contains the different energies and temperature as a function of time. The calculations are done in the micro-canonical ensemble which means that the total energy (the sum of the potential which is the total energy given by SIRIUS and the kinetic energy) is conserved during the integration process. It is possible to compare these results with QE, but instead of doing the molecular dynamics with QE, we take the positions of the atoms at each time step and compute the potential energy for this atom position with QE and plot the result as function of time. +you should obtain a file ''Si7Ge-pos-1.xyz'' that contains the positions of the atoms and ''Si7Ge-1.ener'' that contains the different energies and temperature as a function of time. The calculations are done in the micro-canonical ensemble which means that the total energy (the sum of the potential which is the total energy given by SIRIUS and the kinetic energy) is conserved during the integration process. It is possible to compare these results with QE, but instead of doing the molecular dynamics with QE, we take the positions of the atoms at each time step and compute the potential energy for this atom position with QE.  
 +{{:howto:qe-cp2k-sirius.png|}}<imgcaption image1|>Computation of the potential energy with cp2k/sirius and quantum expresso</imgcaption>
  
howto/running_qe_computation.txt · Last modified: 2021/12/08 10:18 by mtaillefumier