<div class="gmail_quote">A small doubt that I had while following this discussion, please someone correct-me if I'm wrong:<br>Is the following definition right?<br><br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
"[in ab-initio calculations we] do not make any assumption, such as concerning models and/or fitting parameters."<br></blockquote></div><br><br>I'm
saying this because we use, for example, the homogeneous electron gas
model for LDA calculations, nonetheless it is still "ab-initio".<br>
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.<br>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.<br>
<br>Is this right?<br><br>This can even create some discussion if some new functionals can be called "ab-initio" or not...<br><font color="#888888"><br>Leonardo Matheus<br>IF-USP / Brazil</font></div>