[Debichem-devel] Package categories

[Muammar El Khatib]

Hi,

I'm sorry if maybe this would be a little bit off topic. However, I cannot talk
to many people about Quantum mechanics :) So here I go.

Michael Banck wrote:
> On Sun, Jun 29, 2008 at 07:03:58PM +0100, Chris Walker wrote:
>> == Chemistry ===
>> field::chemistry
>>
>> === Structure calculation ===
>>
>> ==== Abinitio  ====
>> (should DFT be listed separately here?
> 
> DFT is ab initio, despite all rumours.
>  

Are you sure about this? I mean as far as I have studied, DFT is not considered
as Ab Initio (some people say yes, others no). Maybe calculation quality is as
good as Ab Initio (DFT takes care about electronic correlation) but DFT starts
from the premise that the electronic density is taken as the basic quantity. So
the electronic density is the function taken for the functional (in this case
the energy) while Ab Initio (like Hartree - Fock for instance) are based on the
many-electron wavefunctions. On the other hand DFT uses parameters derived from
_empirical data_, or from more complex calculations and in that moment is when
DFT does not follow the "calculations from first principles" (where no empirical
data is used).

IMHO DFT should be listed separately.


Regards,
-- 
Muammar El Khatib.
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