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-initio". 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 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20081221/0cb7751e/attachment.htm