Enthalpy of vaporization calculation in CP2K
bharats... at gmail.com
Fri Dec 5 15:17:44 UTC 2014
This is friendly reminder. Any suggestions?
On Wednesday, December 3, 2014 12:56:10 PM UTC-5, bharat wrote:
> Hello Experts,
> I am trying to reproduce Enthalpy of vaporization using PM3.
> Here are my calculation:
> (I took Total energy value from CP2K output file as an Internal energy,
> average is calculated over the MD. Experimental density is used for the
> constant volume for both liquid and vapor calculation). Am I taking correct
> energy value for internal energy?
> U_vapor(Avg) = -20797.3 eV
> U_liquid(Avg) = -20802.9 eV
> Delta_U = 5.6 eV
> I divided with 64 (# of water molecules) and converted to kcal/mol
> = 2.02 kcal/mol
> I got the half value (reported value is 4.00 kcal/mol in G. Murdachaew et
> al. J. Phys. Chem. A 115, 6046 (2011)). Because of this value, I got only
> ~2.60 kcal/mol (RT= ~0.60 kcal/mol) of enthalpy of vaporization (Delta_H =
> delta_U + RT).
> Can anyone please tell me where I am doing wrong? Where is the factor 2
> Thank you.
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