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--- exercises:geo_opt [2022/09/08 12:42] – created jglan
+++ exercises:geo_opt [2022/09/08 12:42] (current) – removed jglan
@@ Line 1: / Line 1: @@
-======= Geometry Optimization =======
-In this exercise, you will perform geometry optimization using DFT. See [[https://manual.cp2k.org/cp2k-2022_1-branch/CP2K_INPUT/MOTION/GEO_OPT.html|GEO_OPT]]
-Note the different ''RUN_TYPE'' and the changed ''PROJECT'' name. The latter is not strictly necessary but recommended since CP2K automatically creates additional files using this project name as a prefix.
-<code - H2O.inp >
-&GLOBAL
-  PROJECT H2O
-  RUN_TYPE GEO_OPT
-  PRINT_LEVEL MEDIUM
-&END GLOBAL
-&MOTION
-  &GEO_OPT
-    MAX_ITER 3000
-    OPTIMIZER BFGS    #Most efficient minimizer, but only for 'small' systems
-  &END GEO_OPT
-&END MOTION
-&FORCE_EVAL
-  METHOD Quickstep              ! Electronic structure method (DFT,...)
-  &DFT
-    BASIS_SET_FILE_NAME  BASIS_MOLOPT
-    POTENTIAL_FILE_NAME  POTENTIAL
-    &POISSON                    ! Solver requested for non periodic calculations
-      PERIODIC NONE
-      PSOLVER  WAVELET          ! Type of solver
-    &END POISSON
-    &SCF                        ! Parameters controlling the convergence of the scf. This section should not be changed.
-      SCF_GUESS ATOMIC
-      EPS_SCF 1.0E-6
-      MAX_SCF 300
-    &END SCF
-    &XC                        ! Parameters needed to compute the electronic exchange potential
-      &XC_FUNCTIONAL PBE
-      &END XC_FUNCTIONAL
-    &END XC
-  &END DFT
-  &SUBSYS
-    &CELL
-      ABC 10 10 10
-      PERIODIC NONE              ! Non periodic calculations. That's why the POISSON section is needed
-    &END CELL
-    &TOPOLOGY                    ! Section used to center the atomic coordinates in the given box. Useful for big molecules
-      &CENTER_COORDINATES
-      &END
-      COORD_FILE_FORMAT xyz
-      COORD_FILE_NAME  ./H2O.xyz
-    &END
-    &KIND H
-      ELEMENT H
-      BASIS_SET DZVP-MOLOPT-GTH
-      POTENTIAL GTH-PBE-q1
-    &END KIND
-    &KIND O
-      ELEMENT C
-      BASIS_SET DZVP-MOLOPT-GTH
-      POTENTIAL GTH-PBE-q6
-    &END KIND
-  &END SUBSYS
-&END FORCE_EVAL
-</code>
-You can also directly open an XYZ file in VMD to visualize it:
-<code>
-$ vmd H2O.xyz
-</code>
-After running this, you will have the following files:
-<code>
-$ ls H2O*
-H2O-1.restart        H2O-1.restart.bak-3  H2O.out          H2O-RESTART.wfn.bak-1
-H2O-1.restart.bak-1  H2O-BFGS.Hessian     H2O-pos-1.xyz    H2O-RESTART.wfn.bak-2
-H2O-1.restart.bak-2  H2O.inp              H2O-RESTART.wfn  H2O-RESTART.wfn.bak-3
-</code>
-Take a look at the output file, especially the following section (repeated the number of cycles it took to reach convergence):
-<code>
- --------  Informations at step =     1 ------------
-  Optimization Method        =                 BFGS
-  Total Energy               =       -14.9417142787
-  Real energy change         =        -0.1955604816
-  Predicted change in energy =        -0.1885432833
-  Scaling factor             =         0.0000000000
-  Step size                  =         0.2677976891
-  Trust radius               =         0.4724315332
-  Decrease in energy         =                  YES
-  Used time                  =               19.018
-  Convergence check :
-  Max. step size             =         0.2677976891
-  Conv. limit for step size  =         0.0030000000
-  Convergence in step size   =                   NO
-  RMS step size              =         0.1458070233
-  Conv. limit for RMS step   =         0.0015000000
-  Convergence in RMS step    =                   NO
-  Max. gradient              =         0.0287243359
-  Conv. limit for gradients  =         0.0004500000
-  Conv. for gradients        =                   NO
-  RMS gradient               =         0.0180771987
-  Conv. limit for RMS grad.  =         0.0003000000
-  Conv. for gradients        =                   NO
- ---------------------------------------------------
-</code>
-For each convergence criterion, you see the value which is used to check whether convergence is reached and convergence is only reached if all of them are satisfied simultaneously.