In my opinion with small hills deposited every 100 fs, you’re unlikely to converge the Metadynamics bias. <div dir="ltr"></div><div dir="ltr">You should have a look at J. Phys. Chem. B 2005, 109, 14, 6714–6721 <a href="https://doi.org/10.1021/jp045424k">https://doi.org/10.1021/jp045424k</a>, on choosing the optimal parameters for ab initio metadynamics. However, even with increased bias deposition rate, it is possible that meta dynamics bias convergence could take more than hundreds or thousands of ps depending on the system, although it’s hard to say. Maybe you can have a qualitative intepretation if you are close to convergence and do not require accurate barriers, and rather need orders of magnitude.</div><div dir="ltr">Take care :) </div><div dir="ltr">Q. </div> <div class="gmail_quote"><div dir="auto" class="gmail_attr">Le dimanche 16 février 2025 à 10:19:16 UTC+1, SAURABH SINGH a écrit : </div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><blockquote type="cite" style="color:rgb(34,34,34);font-family:Arial,Helvetica,sans-serif;font-size:small"><div dir="ltr">Thank you Quentin My system consists of simple molecules Cl CO2 and H2O &GLOBAL PROJECT 1a RUN_TYPE MD PRINT_LEVEL MEDIUM &END GLOBAL #&EXT_RESTART # RESTART_FILE_NAME 1a-1.restart #&END EXT_RESTART &MOTION &MD ENSEMBLE NVT # ENSEMBLE NVE STEPS 50000 TIMESTEP 1 TEMPERATURE 300.0 TEMP_TOL 100 &THERMOSTAT &NOSE LENGTH 3 # 3 is the default MTS 2 # 2 is the default TIMECON 300.0 YOSHIDA 3 # 3 is the default &END NOSE &END THERMOSTAT &END MD &FREE_ENERGY &METADYN DO_HILLS NT_HILLS 100 WW [kcalmol] 0.5 &METAVAR SCALE 0.2 COLVAR 1 &WALL TYPE QUADRATIC POSITION [angstrom] 3.0 &QUADRATIC DIRECTION WALL_PLUS K [kcalmol] 100.0 &END &END &END METAVAR &METAVAR SCALE 0.2 COLVAR 2 &WALL TYPE QUADRATIC POSITION [angstrom] 3 &QUADRATIC DIRECTION WALL_PLUS K [kcalmol] 100.0 &END &END &END METAVAR &PRINT &COLVAR COMMON_ITERATION_LEVELS 3 &EACH MD 1 &END &END &HILLS COMMON_ITERATION_LEVELS 3 &EACH MD 1 &END &END &END &END METADYN &END &PRINT &RESTART_HISTORY &EACH MD 100 &END &END RESTART_HISTORY &VELOCITIES &EACH MD 1 &END &END # Normal restart file &RESTART &EACH MD 1 &END &END RESTART &END PRINT &END MOTION &FORCE_EVAL METHOD Quickstep ! Electronic structure method (DFT,...) &DFT CHARGE = 0 MULTIPLICITY = 2 LSD BASIS_SET_FILE_NAME BASIS_MOLOPT.dat POTENTIAL_FILE_NAME GTH_POTENTIALS.dat # if WFN restart is required WFN_RESTART_FILE_NAME 1a.wfn &MGRID #CUTOFF 1000 CUTOFF 360 NGRIDS 4 REL_CUTOFF 60 &END MGRID &QS METHOD GPW EPS_DEFAULT 1.0E-10 # 1.0E-10 is the default &END QS &SCF SCF_GUESS RESTART EPS_SCF 1.0E-5 # 1.0E-5 is the default MAX_SCF 600 # 50 is the default &OT MINIMIZER CG PRECONDITIONER FULL_ALL LINESEARCH 3PNT &END &OUTER_SCF EPS_SCF 1.0E-5 # 1.0E-5 is the default MAX_SCF 20 # Keep > 100 when OT is on &END &END SCF &XC &XC_FUNCTIONAL PBE &END XC_FUNCTIONAL &vdW_POTENTIAL DISPERSION_FUNCTIONAL PAIR_POTENTIAL # POTENTIAL_TYPE is alias to DISPERSION_FUNCTIONAL &PAIR_POTENTIAL TYPE DFTD3 PARAMETER_FILE_NAME dftd3.dat REFERENCE_FUNCTIONAL PBE &END PAIR_POTENTIAL &END vdW_POTENTIAL &END XC &POISSON ! Solver requested for non periodic calculations PERIODIC NONE ! Type of solver POISSON_SOLVER MT &END POISSON &END DFT &SUBSYS &CELL A 20.0000000 0.00000000 0.00000000 B 0.00000000 20.0000000 0.00000000 C 0.00000000 0.00000000 20.00000000 PERIODIC NONE ! Non periodic calculations. That's why the POISSON section is needed &END CELL &TOPOLOGY ! Section used to center the atomic COORD_FILE_FORMAT xyz COORD_FILE_NAME <a href="http://1a.xyz/" style="color:rgb(17,85,204)" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=fr&q=http://1a.xyz/&source=gmail&ust=1739870180589000&usg=AOvVaw3K0WW9abwk_8xCosYXPq_Z">1a.xyz</a> &CENTER_COORDINATES &END &END &KIND C ELEMENT C BASIS_SET DZVP-MOLOPT-SR-GTH-q4 POTENTIAL GTH-PBE-q4 &END KIND &KIND H ELEMENT H BASIS_SET DZVP-MOLOPT-SR-GTH-q1 POTENTIAL GTH-PBE-q1 &END KIND &KIND Cl ELEMENT Cl BASIS_SET DZVP-MOLOPT-SR-GTH-q7 POTENTIAL GTH-PBE-q7 &END KIND &KIND O ELEMENT O BASIS_SET DZVP-MOLOPT-SR-GTH-q6 POTENTIAL GTH-PBE-q6 &END KIND &COLVAR &DISTANCE ATOMS 5 3 &END DISTANCE &END COLVAR &COLVAR &DISTANCE ATOMS 7 3 &END DISTANCE &END COLVAR &END SUBSYS &END FORCE_EVAL I have attached my input file </div></blockquote> <div class="gmail_quote"><div dir="auto" class="gmail_attr">On Friday, February 14, 2025 at 3:34:42 PM UTC+5:30 Quentin Pessemesse wrote: </div><blockquote class="gmail_quote" style="margin:0 0 0 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>Hello, </div><div>I think you need to provide a bit more information such as the total time of your simulation, the type of system and maybe an input file. Metadynamics can be very long to converge, and it might be impossible to achieve convergence with ab initio depending on your CV for instance. If you observe crossing, it means that your CV is able to "push" the system over the barrier which is already a good sign. </div><div>The plumed tutorials and google groups have information on how to understand how to see if a metadynamics simulation is converged, for instance:</div><div><a href="https://groups.google.com/g/plumed-users/c/3R9CghiH8EE" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=fr&q=https://groups.google.com/g/plumed-users/c/3R9CghiH8EE&source=gmail&ust=1739870180589000&usg=AOvVaw2R4LS7B47dgf0rYReT7iiE">https://groups.google.com/g/plumed-users/c/3R9CghiH8EE</a></div><div><a href="https://www.plumed.org/doc-v2.9/user-doc/html/master-_i_s_d_d-2.html" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=fr&q=https://www.plumed.org/doc-v2.9/user-doc/html/master-_i_s_d_d-2.html&source=gmail&ust=1739870180589000&usg=AOvVaw3XlmGUthliaNzYmXh0CyDU">https://www.plumed.org/doc-v2.9/user-doc/html/master-_i_s_d_d-2.html</a></div><div>There are other sampling methods that can help you achieve convergence of a free energy barrier if metadynamics does not work for your system.</div><div>Take care,</div><div>Quentin</div> <div class="gmail_quote"><div dir="auto" class="gmail_attr">Le mercredi 12 février 2025 à 13:01:43 UTC+1, SAURABH SINGH a écrit : </div><blockquote class="gmail_quote" style="margin:0 0 0 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hii I am facing a problem in metadynamics study I am using normal metadynamics. In my case I am getting the multiple recrossing, but my energy is not converging I am using wall height 1 kcal/mol and sigma as 0.3 Is it indicating issues with CV? I will be very grateful if you can give some valuable insights Thank you</blockquote></div></blockquote></div></blockquote></div> -- You received this message because you are subscribed to the Google Groups "cp2k" group. To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp2k+unsubscribe@googlegroups.com">cp2k+unsubscribe@googlegroups.com</a>. To view this discussion visit <a href="https://groups.google.com/d/msgid/cp2k/11cfc1fd-76c4-41b3-85d5-f7113d2bfaf7n%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/11cfc1fd-76c4-41b3-85d5-f7113d2bfaf7n%40googlegroups.com</a>.