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--- exercises:2015_cecam_tutorial:forcefields [2015/09/01 21:36] – mwatkins
+++ exercises:2015_cecam_tutorial:forcefields [2015/09/01 21:42] – mwatkins
@@ Line 62: / Line 62: @@
   &GEO_OPT
     MINIMIZER LBFGS
+    #just do 100 steps,
+    #we only want to remove bad contacts
     MAX_ITER 100
   &END
+&END MOTION
+</code>
+Now we can start to equilibriate the system in MD. Make a new input file as follows, and run it in the same directory (or tell it where the restart file from the minimization is)
+<code>
+&FORCE_EVAL
+  METHOD FIST
+  &MM
+    &FORCEFIELD
+      parm_file_name toppar/par_all27_prot_lipid.prm
+      parmtype CHM
+      &SPLINE
+         EMAX_SPLINE 1000000
+         RCUT_NB 10.0
+      &END
+    &END FORCEFIELD
+    &POISSON
+      &EWALD
+        EWALD_TYPE spme
+        ALPHA .44
+        GMAX 36
+        O_SPLINE 6
+      &END EWALD
+    &END POISSON
+  &END MM
+  &SUBSYS
+    &CELL
+      ABC 40.685 42.380 46.291
+    &END CELL
+    &TOPOLOGY
+      COORD_FILE_NAME solvate.pdb
+      COORDINATE pdb
+      CONN_FILE_FORMAT psf
+      CONN_FILE_NAME solvate.psf
+    &END TOPOLOGY
+    &PRINT
+      &TOPOLOGY_INFO
+         PSF_INFO
+      &END
+    &END
+  &END SUBSYS
+&END FORCE_EVAL
+&GLOBAL
+  PROJECT ubiquitin_md
+  RUN_TYPE MD
+&END GLOBAL
+&EXT_RESTART
+  RESTART_FILE_NAME ubiquitin_mini-1.restart
+  RESTART_DEFAULT F
+  RESTART_POS T
+&END EXT_RESTART
+&MOTION
   &MD
     ENSEMBLE NVT
@@ Line 79: / Line 136: @@
 &END MOTION
 </code>
+We take the coordinates from previous minimization run using the external restart option in CP2K. Hopefully this works for you and you can explore the MD facilities in the code. You'd need to equilibriate for quite some ns before starting production, maybe including some NPT to make sure the box size is correct.