[Pw_forum] ab initio vs. first principles.
baroni at sissa.it
Mon Dec 22 09:49:39 CET 2008
(although quantum chemists may disagree to some extent)
On Dec 22, 2008, at 2:47 AM, Leonardo Matheus wrote:
> A small doubt that I had while following this discussion, please
> someone correct-me if I'm wrong:
> Is the following definition right?
> "[in ab-initio calculations we] do not make any assumption, such as
> concerning models and/or fitting parameters."
> I'm saying this because we use, for example, the homogeneous
> electron gas model for LDA calculations, nonetheless it is still "ab-
> I think that it's not the use of parameters or models that define a
> first principles method, but from where those parameters were taken.
> If your parameters came from experimental values, it's somewhat
> empirical (or semi-empirical at least), if you used just theoretical
> values (even if using a simplified model) it can be called ab-initio.
> Is this right?
> This can even create some discussion if some new functionals can be
> called "ab-initio" or not...
> Leonardo Matheus
> IF-USP / Brazil
> Pw_forum mailing list
> Pw_forum at pwscf.org
Stefano Baroni - SISSA & DEMOCRITOS National Simulation Center -
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