Re: [Avogadro-Discuss] positive total energy of fellerene in Avogadro

2015-12-01 Thread Geoffrey Hutchison 
> I have made the fullerene (C60) in Avogadro and get a total energy of 
> +4.323.01kJ/mol. with different force field again I get a positive number.

Force fields use an empirical model, so the "total energies" are relative. 
Certainly fullerenes have a high ring strain energy.

That's not to say that C60 isn't stable, but if you're trying to get accurate 
heats of formation, I'd use a semiempirical method (e.g., PM7, MOPAC) or DFT.

Best regards,
-Geoff
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[Avogadro-Discuss] positive total energy of fellerene in Avogadro

2015-12-01 Thread Mojtaba Akbarzadeh 
Dear Scientist

I have made the fullerene (C60) in Avogadro and get a total energy of
+4.323.01kJ/mol. with different force field again I get a positive number.

is there anything wrong about it?!
shouldn't the total energy of the molecule be negative to be stable?!

Thank you so much in advance

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Mojtaba Akbarzadeh
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