Enthalpy of vaporization calculation in CP2K

[bharat]

Hello,
This is friendly reminder. Any suggestions?

Bharat

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 
> missing?
>
> Thank you.
>
> Bharat 
>
>
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