[CP2K:10562] unit

[simin pahlavi]

Hello Lian,
Thank you so much for your reply and comment.
Best regards
Simin

On Monday, July 23, 2018 at 3:59:45 PM UTC+2, IBethune wrote:
>
> 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 
> https://github.com/cp2k/cp2k/blob/master/cp2k/src/force_fields_ext.F) 
>
> !      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. 
> https://manual.cp2k.org/cp2k-5_1-branch/CP2K_INPUT/FORCE_EVAL/MM/FORCEFIELD/BEND.html 
>
> Cheers 
>
> - Iain 
>
>
> -- 
>
> Iain Bethune 
> Technical Programme Manager, STFC Hartree Centre 
>
> Email: iain... at stfc.ac.uk <javascript:> 
> 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 <simi... at gmail.com 
> <javascript:>> 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 
> > 
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