<div dir="ltr"> Hello Lian,<div>Thank you so much for your reply and comment.</div><div>Best regards</div><div>Simin</div><div> On Monday, July 23, 2018 at 3:59:45 PM UTC+2, IBethune wrote:<blockquote class="gmail_quote" style="margin: 0;margin-left: 0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;">Hi Simin, The forcefield constants in the CHARMM format are expressed in kcal/mol and Angstrom units system (this is the convention that the CHARMM community uses). CP2K reads a CHARMM-formatted file and converts to CP2K internal units (see <a href="https://github.com/cp2k/cp2k/blob/master/cp2k/src/force_fields_ext.F" target="_blank" rel="nofollow" onmousedown="this.href='https://www.google.com/url?q\x3dhttps%3A%2F%2Fgithub.com%2Fcp2k%2Fcp2k%2Fblob%2Fmaster%2Fcp2k%2Fsrc%2Fforce_fields_ext.F\x26sa\x3dD\x26sntz\x3d1\x26usg\x3dAFQjCNHEII2poDHpNZa_CokBoPCStJxByw';return true;" onclick="this.href='https://www.google.com/url?q\x3dhttps%3A%2F%2Fgithub.com%2Fcp2k%2Fcp2k%2Fblob%2Fmaster%2Fcp2k%2Fsrc%2Fforce_fields_ext.F\x26sa\x3dD\x26sntz\x3d1\x26usg\x3dAFQjCNHEII2poDHpNZa_CokBoPCStJxByw';return true;">https://github.com/cp2k/cp2k/blob/master/cp2k/src/force_fields_ext.F</a>) ! UNITS for Kb: [(kcal/mol)/(A^2)] to [Eh/(AU^2)] ! UNITS for Ktheta: [(kcal/mol)/(rad^2)] to [Eh/(rad^2)] ! UNITS for Kub: [(kcal/mol)/(A^2)] to [Eh/(AU^2)] ! UNITS for Kphi: [(kcal/mol)] to [Eh] ! UNITS for Kpsi: [(kcal/mol)/(rad^2)] to [Eh/(rad^2)] For force-fields that you define explicitly using the MM%FORCEFIELD sub-sections, you can specify whatever dimensionally consistent units you like. By default CP2K uses atomic units (hartree and bohr). See e.g. <a href="https://manual.cp2k.org/cp2k-5_1-branch/CP2K_INPUT/FORCE_EVAL/MM/FORCEFIELD/BEND.html" target="_blank" rel="nofollow" onmousedown="this.href='https://www.google.com/url?q\x3dhttps%3A%2F%2Fmanual.cp2k.org%2Fcp2k-5_1-branch%2FCP2K_INPUT%2FFORCE_EVAL%2FMM%2FFORCEFIELD%2FBEND.html\x26sa\x3dD\x26sntz\x3d1\x26usg\x3dAFQjCNEFQyRnX5nTZIMv5xcm9CyNOKHueA';return true;" onclick="this.href='https://www.google.com/url?q\x3dhttps%3A%2F%2Fmanual.cp2k.org%2Fcp2k-5_1-branch%2FCP2K_INPUT%2FFORCE_EVAL%2FMM%2FFORCEFIELD%2FBEND.html\x26sa\x3dD\x26sntz\x3d1\x26usg\x3dAFQjCNEFQyRnX5nTZIMv5xcm9CyNOKHueA';return true;">https://manual.cp2k.org/cp2k-5_1-branch/CP2K_INPUT/FORCE_EVAL/MM/FORCEFIELD/BEND.html</a> Cheers - Iain -- Iain Bethune Technical Programme Manager, STFC Hartree Centre Email: <a href="javascript:" target="_blank" gdf-obfuscated-mailto="dbnMBHKiBwAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">iain...@stfc.ac.uk</a> Twitter: @IainBethune @PrimeGrid @CP2Kproject Tel: +44 (0)1925 603735 Mob: +44 (0)7598317015 Addr: Hartree Centre, Sci-Tech Daresbury, Keckwick, Warrington, WA4 4AD > On 23 Jul 2018, at 13:51, simin pahlavi <<a href="javascript:" target="_blank" gdf-obfuscated-mailto="dbnMBHKiBwAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">simi...@gmail.com</a>> wrote: > > Dear Cp2k users, > I have a question about units. > In exercises ( Fist ) parts of cp2k webpage , the units of for example force constants (in separate file for potentials) is kcal.mol/An ^2 without any changing in unit in inp file, while according to the cp2k manual is supposed to be hartee/boh^2. And same for the other constants and parametrs. > Does anybody can describe why without, changing the units, cp2k automatically find out that for instance force constants in charm potentials is written in kcal/mol An^2 unit? > Best regards > Simin > > -- > 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="javascript:" target="_blank" gdf-obfuscated-mailto="dbnMBHKiBwAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">cp2k+uns...@googlegroups.com</a>. > To post to this group, send email to <a href="javascript:" target="_blank" gdf-obfuscated-mailto="dbnMBHKiBwAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">cp...@googlegroups.com</a>. > Visit this group at <a href="https://groups.google.com/group/cp2k" target="_blank" rel="nofollow" onmousedown="this.href='https://groups.google.com/group/cp2k';return true;" onclick="this.href='https://groups.google.com/group/cp2k';return true;">https://groups.google.com/group/cp2k</a>. > For more options, visit <a href="https://groups.google.com/d/optout" target="_blank" rel="nofollow" onmousedown="this.href='https://groups.google.com/d/optout';return true;" onclick="this.href='https://groups.google.com/d/optout';return true;">https://groups.google.com/d/optout</a>. </blockquote></div></div>