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<p>You may want to go by how Karlheinz Schwarz describes them.</p>
<p>ab initio translates to "first principles" meaning no
experimental data is needed and just physical constants can be
plugged in to solve the theoretical equation.</p>
<p>The exact statement Schwarz uses in [1] is:<br>
</p>
<p><i>The advantage of</i><i> first-principle (ab initio) methods
lies in the fact that</i><i> they can be carried out without
knowing any experi</i><i>mental data of the system. </i><br>
</p>
<p>Wikipedia says [2]:<br>
</p>
<p><i>Ab initio means "from first principles" or "from the
beginning", implying that the only inputs into an ab initio
calculation are physical constants.</i><br>
</p>
<p>DFT (Density Functional Theory) means a quantum mechanical model
were a many-body problem can be solved using a density functional.</p>
<p>The exact statements Schwarz uses in [3] are:<br>
</p>
<p><i>In this way DFT is a universal approach to the quantum
mechanical many-body problem, where the system of interacting
electrons is mapped in a unique manner onto an effective
non-interacting system that has the same total density.</i><br>
</p>
<p><i>According to DFT all that is needed is the density ρ(r) which
only depends on the position r, i.e. on three coordinates.</i><br>
</p>
<p>Wikipedia uses the words:<br>
</p>
<p><i>Using this theory, the properties of a many-electron system
can be determined by using functionals, i.e. functions of
another function. In the case of DFT, these are functionals of
the spatially dependent electron density.</i><br>
</p>
<p>Based on the above, WIEN2k calculations can be both DFT and ab
initio.</p>
<p>For further details, see Schwarz's publications [1,3] or you may
look at other explanations you might find in a textbook or on the
Internet such as [5,6].<br>
</p>
<br>
[1] <a class="moz-txt-link-freetext"
href="https://doi.org/10.1016/S0022-4596(03)00213-5">https://doi.org/10.1016/S0022-4596(03)00213-5</a><br>
[2] <a class="moz-txt-link-freetext"
href="https://en.wikipedia.org/wiki/Ab_initio_quantum_chemistry_methods">https://en.wikipedia.org/wiki/Ab_initio_quantum_chemistry_methods</a><br>
[3] <a class="moz-txt-link-freetext"
href="http://dx.doi.org/10.5772/59108">http://dx.doi.org/10.5772/59108</a><br>
[4] <a class="moz-txt-link-freetext"
href="https://en.wikipedia.org/wiki/Density_functional_theory">https://en.wikipedia.org/wiki/Density_functional_theory</a><br>
[5] <a class="moz-txt-link-freetext" href="https://dft.uci.edu/doc/g1.pdf">https://dft.uci.edu/doc/g1.pdf</a><br>
[6]
<a class="moz-txt-link-freetext" href="http://ccl.net/chemistry/resources/messages/1995/05/17.001-dir/index.html">http://ccl.net/chemistry/resources/messages/1995/05/17.001-dir/index.html</a>
<p>Kind Regards,</p>
Gavin<br>
WIEN2k user<br>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">On 7/6/2022 7:18 AM, ben amara imen
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CACAZvnqitf+W9zKW3FWf_=QJOZsFn_x_svp_nqyofTHjRTibFg@mail.gmail.com">
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<div dir="auto">Dears users
<div dir="auto"><br>
</div>
<div dir="auto">Can someone please explain the difference
between ab initio calculation and DFT. </div>
<div dir="auto"><br>
</div>
<div dir="auto">As I know , ab initio calculation is based on
wave function without any empirical parameters . DFT is based
on density of charge but it uses the empirical parameters
(within Exchange-correlation potentiel PBE , GGA..).</div>
<div dir="auto"><br>
</div>
<div dir="auto">Is it correct ?.</div>
<div dir="auto"><br>
</div>
<div dir="auto">If it is correct , why some papers consider DFT
as ab initio calculation. </div>
<div dir="auto"><br>
</div>
<div dir="auto">Thanks </div>
<div dir="auto"><br>
</div>
<div dir="auto"><br>
</div>
<div dir="auto">Best regards <br>
</div>
</div>
</blockquote>
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