Hi<div>I work with two-dimensional hexagonal boron nitride. The valency of the N （B) element calculated by XTB is -0.45(0.45), and I've seen some papers give it as -2.6. I don't know if that's right. I've been told by some scholars that changes in charge are important. The value of charge is affected by the way it is divided, and the value of charge is also different from the way it is divided, so I do not care about the size of the value of charge. (I don't know what you mean by physically sound ) I have calculated the mechanical properties of hexagonal boron nitride with XTB, and the results are in a reasonable range. </div><div> </div><div>regards</div><div>EN</div><div> </div><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Friday, March 1, 2024 at 4:58:05 PM UTC+8 Jürg Hutter wrote: </div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Hi did you check that the xTB Hamiltonian correctly describes your basic system? Are fundamental properties correct (without EField)? You also disable the check on atomic charges, did you make sure that the final atomic charges (again without Efield) are physically sound? regards JH ________________________________________ From: <a href data-email-masked rel="nofollow">cp...@googlegroups.com</a> <<a href data-email-masked rel="nofollow">cp...@googlegroups.com</a>> on behalf of Evelyn Navarro <<a href data-email-masked rel="nofollow">easa...@gmail.com</a>> Sent: Thursday, February 29, 2024 3:33 PM To: cp2k Subject: Re: [CP2K:19978] Does the boundary setting affect the charge distribution under the electric field? Hi I tried to use the periodic electric field to calculate the two-dimensional piezoelectric material at the periodic boundary, but the charge seemed to accumulate towards the middle of the two-dimensional material, which was unreasonable. The normal ones should gather towards both ends of the material. I want to know what the problem is. (This does not seem to be a problem with aperiodic boundaries.) &GLOBAL PROJECT 468-zhouqi-0.003d-xyzbianjie-2024-M-EWALD PRINT_LEVEL LOW RUN_TYPE MD &END GLOBAL &FORCE_EVAL METHOD Quickstep &SUBSYS &CELL ABC 38.9946780817 32.5196269485 100.000 PERIODIC XYZ #Direction of applied PBC (geometry aspect) &END CELL &TOPOLOGY COORD_FILE_FORMAT XYZ COORD_FILE_NAME <a href="http://468.xyz" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en&q=http://468.xyz&source=gmail&ust=1709386752068000&usg=AOvVaw0OT9xVmmepYXmMnCu_cFLw">468.xyz</a> &CENTER_COORDINATES #Centering the atoms in the box &END &END # &VELOCITY #You can set initial atomic velocities in this section # &END VELOCITY &END SUBSYS &DFT # WFN_RESTART_FILE_NAME 400-RESTART.wfn CHARGE 0 #Net charge MULTIPLICITY 1 #Spin multiplicity &PERIODIC_EFIELD INTENSITY 0.003 POLARISATION -1.00000 0.00000 0.00000 &END &QS EPS_DEFAULT 1E-10 #This is default. Set all EPS_xxx to values such that the energy will be correct up to this value EXTRAPOLATION ASPC #Extrapolation for wavefunction during e.g. MD. ASPC is default, PS also be used EXTRAPOLATION_ORDER 3 #Order for PS or ASPC extrapolation. 3 is default METHOD xTB &xTB DO_EWALD T CHECK_ATOMIC_CHARGES F #xTB calculation often crashes without setting this to false &PARAMETER DISPERSION_PARAMETER_FILE dftd3.dat PARAM_FILE_NAME xTB_parameters &END PARAMETER &END xTB &END QS &POISSON &EWALD ALPHA 1.0 EWALD_TYPE SPME GMAX 75 &END EWALD PERIODIC XYZ #Direction(s) of PBC for calculating electrostatics PSOLVER PERIODIC ##ANALYTIC #The way to solve Poisson equation &END POISSON &SCF MAX_SCF 20 #Maximum number of steps of inner SCF EPS_SCF 1.0E-05 #Convergence threshold of density matrix of inner SCF # SCF_GUESS RESTART #Use wavefunction from WFN_RESTART_FILE_NAME file as initial guess &OT PRECONDITIONER FULL_SINGLE_INVERSE MINIMIZER DIIS #CG is worth to consider in difficult cases LINESEARCH 2PNT #1D line search algorithm for CG. 2PNT is default, 3PNT is better but more costly. GOLD is best but very expensive &END OT &OUTER_SCF MAX_SCF 20 #Maximum number of steps of outer SCF EPS_SCF 1.0E-05 #Convergence threshold of outer SCF &END OUTER_SCF &PRINT &RESTART OFF #Do not generate wfn file to suppress meaningless I/O cost &END RESTART &END PRINT &END SCF &PRINT &MULLIKEN FILENAME muliken &EACH MD 1 &END PRINT_ALL F #If T, then printing full net AO and overlap population matrix &END MULLIKEN &END PRINT &END DFT &END FORCE_EVAL &MOTION &MD ENSEMBLE NVT STEPS 250000 #Number of steps to run TIMESTEP 1.0 #Step size in fs. Decrease it properly for high temperature simulation TEMPERATURE 5 #Initial and maintained temperature (K) &THERMOSTAT TYPE NOSE &END THERMOSTAT &END MD &CONSTRAINT &FIXED_ATOMS #Set atoms to be fixed COMPONENTS_TO_FIX XYZ #Which fractional components will be fixed, can be X, Y, Z, XY, XZ, YZ, XYZ LIST 357..468 &END FIXED_ATOMS &END CONSTRAINT &PRINT &TRAJECTORY &EACH MD 1 #Output frequency of coordinate &END EACH FORMAT xyz &END TRAJECTORY &RESTART BACKUP_COPIES 0 #Maximum number of backing up restart file, 0 means never &EACH MD 100 #Frequency of updating last restart file. Default is 20 &END EACH &END RESTART &RESTART_HISTORY &EACH MD 1000 #How many steps a history .restart file is generated. Default is 500 &END EACH &END RESTART_HISTORY &END PRINT &END MOTION On Monday, February 26, 2024 at 5:07:59 PM UTC+8 Jürg Hutter wrote: Hi you are using a probably not tested combination of features. xTB with 2D periodicity and external electrical field (and hoping for the correct default Ewald setting) might not result in a correct setup. You should also use the PERIODIC_EFIELD option. I would suggest to simplify your system: use 3 D periodic cell with a large vacuum space (e.g. 80 A). This should correctly choose the Ewald settings and together with PERIODIC_EFIELD might work. regards JH ________________________________________ From: <a href data-email-masked rel="nofollow">cp...@googlegroups.com</a> <<a href data-email-masked rel="nofollow">cp...@googlegroups.com</a>> on behalf of Evelyn Navarro <<a href data-email-masked rel="nofollow">easa...@gmail.com</a>> Sent: Friday, February 23, 2024 2:03 PM To: cp2k Subject: [CP2K:19964] Does the boundary setting affect the charge distribution under the electric field? Dear all I was studying the charge changes of two-dimensional piezoelectric materials under electric fields, and found that when the boundary is set as a period, the charge is actually concentrated in the middle of the material, which is not understandable. But if you use aperiodic boundaries, the charge will accumulate towards both ends of the material, which is normal. I tried the electric field and the periodic electric field respectively, and as long as the boundary is periodic, the charge will gather in the middle, which is incomprehensible, and I want to know why. What I want to study is periodic materials, and this periodic boundary is unavoidable. &GLOBAL PROJECT 468-zhouqi-0.004d-xybianjie-2024 PRINT_LEVEL LOW RUN_TYPE MD &END GLOBAL &FORCE_EVAL METHOD Quickstep &SUBSYS &CELL ABC 38.9946780817 32.5196269485 20.000 PERIODIC XY #Direction of applied PBC (geometry aspect) &END CELL &TOPOLOGY COORD_FILE_FORMAT XYZ COORD_FILE_NAME <a href="http://468.xyz" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en&q=http://468.xyz&source=gmail&ust=1709386752068000&usg=AOvVaw0OT9xVmmepYXmMnCu_cFLw">468.xyz</a><<a href="http://468.xyz" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en&q=http://468.xyz&source=gmail&ust=1709386752068000&usg=AOvVaw0OT9xVmmepYXmMnCu_cFLw">http://468.xyz</a>> &CENTER_COORDINATES #Centering the atoms in the box &END &END # &VELOCITY #You can set initial atomic velocities in this section # &END VELOCITY &END SUBSYS &DFT # WFN_RESTART_FILE_NAME 400-RESTART.wfn CHARGE 0 #Net charge MULTIPLICITY 1 #Spin multiplicity &EFIELD INTENSITY 0.004 POLARISATION -1.00000 0.00000 0.00000 &END &QS EPS_DEFAULT 1E-10 #This is default. Set all EPS_xxx to values such that the energy will be correct up to this value EXTRAPOLATION ASPC #Extrapolation for wavefunction during e.g. MD. ASPC is default, PS also be used EXTRAPOLATION_ORDER 3 #Order for PS or ASPC extrapolation. 3 is default METHOD xTB &xTB CHECK_ATOMIC_CHARGES F #xTB calculation often crashes without setting this to false &PARAMETER DISPERSION_PARAMETER_FILE dftd3.dat PARAM_FILE_NAME xTB_parameters &END PARAMETER &END xTB &END QS &POISSON PERIODIC XY #Direction(s) of PBC for calculating electrostatics PSOLVER ANALYTIC #The way to solve Poisson equation &END POISSON &SCF MAX_SCF 20 #Maximum number of steps of inner SCF EPS_SCF 1.0E-05 #Convergence threshold of density matrix of inner SCF # SCF_GUESS RESTART #Use wavefunction from WFN_RESTART_FILE_NAME file as initial guess &OT PRECONDITIONER FULL_SINGLE_INVERSE MINIMIZER DIIS #CG is worth to consider in difficult cases LINESEARCH 2PNT #1D line search algorithm for CG. 2PNT is default, 3PNT is better but more costly. GOLD is best but very expensive &END OT &OUTER_SCF MAX_SCF 20 #Maximum number of steps of outer SCF EPS_SCF 1.0E-05 #Convergence threshold of outer SCF &END OUTER_SCF &PRINT &RESTART OFF #Do not generate wfn file to suppress meaningless I/O cost &END RESTART &END PRINT &END SCF &END DFT &END FORCE_EVAL &MOTION &MD ENSEMBLE NVT STEPS 250000 #Number of steps to run TIMESTEP 1.0 #Step size in fs. Decrease it properly for high temperature simulation TEMPERATURE 5 #Initial and maintained temperature (K) &THERMOSTAT TYPE NOSE &END THERMOSTAT &END MD &CONSTRAINT &FIXED_ATOMS #Set atoms to be fixed COMPONENTS_TO_FIX XYZ #Which fractional components will be fixed, can be X, Y, Z, XY, XZ, YZ, XYZ LIST 357..468 &END FIXED_ATOMS &END CONSTRAINT &PRINT &TRAJECTORY &EACH MD 1 #Output frequency of coordinate &END EACH FORMAT xyz &END TRAJECTORY &RESTART BACKUP_COPIES 0 #Maximum number of backing up restart file, 0 means never &EACH MD 100 #Frequency of updating last restart file. Default is 20 &END EACH &END RESTART &RESTART_HISTORY &EACH MD 1000 #How many steps a history .restart file is generated. Default is 500 &END EACH &END RESTART_HISTORY &END PRINT &END MOTION Thanks Evelyn Navarro -- 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 data-email-masked rel="nofollow">cp2k+uns...@googlegroups.com</a><mailto:<a href data-email-masked rel="nofollow">cp2k+uns...@googlegroups.com</a>>. To view this discussion on the web visit <a href="https://groups.google.com/d/msgid/cp2k/0b163d78-c506-4817-97d6-ba7f187a4e85n%40googlegroups.com" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/d/msgid/cp2k/0b163d78-c506-4817-97d6-ba7f187a4e85n%2540googlegroups.com&source=gmail&ust=1709386752068000&usg=AOvVaw1t592MZkpyYDhCHWPjJ1N7">https://groups.google.com/d/msgid/cp2k/0b163d78-c506-4817-97d6-ba7f187a4e85n%40googlegroups.com</a><<a href="https://groups.google.com/d/msgid/cp2k/0b163d78-c506-4817-97d6-ba7f187a4e85n%40googlegroups.com?utm_medium=email&utm_source=footer" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/d/msgid/cp2k/0b163d78-c506-4817-97d6-ba7f187a4e85n%2540googlegroups.com?utm_medium%3Demail%26utm_source%3Dfooter&source=gmail&ust=1709386752068000&usg=AOvVaw0BN55Xwuul6S4vOyP9ZiH8">https://groups.google.com/d/msgid/cp2k/0b163d78-c506-4817-97d6-ba7f187a4e85n%40googlegroups.com?utm_medium=email&utm_source=footer</a>>. -- 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 data-email-masked rel="nofollow">cp2k+uns...@googlegroups.com</a><mailto:<a href data-email-masked rel="nofollow">cp2k+uns...@googlegroups.com</a>>. To view this discussion on the web visit <a href="https://groups.google.com/d/msgid/cp2k/c242bead-ebad-4fe0-b0ae-d29874facc32n%40googlegroups.com" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/d/msgid/cp2k/c242bead-ebad-4fe0-b0ae-d29874facc32n%2540googlegroups.com&source=gmail&ust=1709386752068000&usg=AOvVaw0SE8pw2_pHWGsiYuggWkaM">https://groups.google.com/d/msgid/cp2k/c242bead-ebad-4fe0-b0ae-d29874facc32n%40googlegroups.com</a><<a href="https://groups.google.com/d/msgid/cp2k/c242bead-ebad-4fe0-b0ae-d29874facc32n%40googlegroups.com?utm_medium=email&utm_source=footer" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/d/msgid/cp2k/c242bead-ebad-4fe0-b0ae-d29874facc32n%2540googlegroups.com?utm_medium%3Demail%26utm_source%3Dfooter&source=gmail&ust=1709386752068000&usg=AOvVaw1ajKEab9PZMfZ2aSRLPrll">https://groups.google.com/d/msgid/cp2k/c242bead-ebad-4fe0-b0ae-d29874facc32n%40googlegroups.com?utm_medium=email&utm_source=footer</a>>. </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 on the web visit <a href="https://groups.google.com/d/msgid/cp2k/f72c9de6-a387-4c31-b852-2d5e63a8266fn%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/f72c9de6-a387-4c31-b852-2d5e63a8266fn%40googlegroups.com</a>.