LAMMPS WWW Site - LAMMPS Documentation - LAMMPS Mailing List Archives
Re: [lammps-users] tip4p water energy values comparison
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [lammps-users] tip4p water energy values comparison


From: 姚懿 <yaoyi92@...24...>
Date: Mon, 10 Aug 2015 17:52:35 -0400

using lj/cut/tip4p/cut and conversion factor 4.184
 
I got

-26.0868216 with your input.

Yi

On Sun, Aug 9, 2015 at 4:57 PM, conor parks <coparks2012@...43...4...> wrote:
Hello,

I was wondering if someone could help me understand some discrepancies I am getting between lammps and accepted water cluster energies using tip4p. Specifically, I am comparing energy values against values from the following site: 

http://www-wales.ch.cam.ac.uk/~wales/CCD/TIP4P-water.html

citation: 
D. J. Wales and M. P. Hodges, Chem. Phys. Lett., 286, 65 (1998)

I have provided the data file for the 2 molecular cluster and input file I am using. I have noticed discrepancies between the two water cluster and twenty one water cluster. I have not tested any of the others yet.

When I run the provided files, I got a total potential energy of (using 4.1868 conversion factor from kcal/mol to j/mol)
lammps total potential energy = -5.7754 (kcal/mol)
lammps total potential energy = -24.18 kj/mol
literature value = -26.08757 kJ/mol. 

if you take the 21 molecular cluster, and create a data file and use my input file, I get
lammps (kcal/mol) :: -217.1854
lammps (kj/mol) :: -909.311
literature value (kj/mol) = -916.07

Could somebody tell me whats going on here?
--
B.S.E in Chemical Engineering, University of Michigan, 2012
PhD candidate in Chemical Engineering, Purdue University

------------------------------------------------------------------------------

_______________________________________________
lammps-users mailing list
lammps-users@...93...urceforge.net
https://lists.sourceforge.net/lists/listinfo/lammps-users




--
Yi Yao
PhD Candidate
Chemistry Department
Caudill 006
University of North Carolina at Chapel Hill