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Dear Guido and others:<br>
<br>
Thanks for your kind reply. I have read the manual and still a
little bit confused. Please point out if i have a wrong
understanding.<br>
<br>
Does "tot_magnetization" parameter is only for induce starting
magnetization, which allowed pw.x to determine during SCF cycles, or
it is used to freeze the value during whole calculation? <br>
<br>
Is this parameter of the same function with:<br>
<span class="Apple-style-span" style="border-collapse: separate;
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text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; font-size: medium;"><span
class="Apple-style-span" style="font-family:
arial,helvetica,sans-serif;">constrained_magnetization='total'
together with </span></span><span class="Apple-style-span"
style="border-collapse: separate; color: rgb(0, 0, 0);
font-family: 'Times New Roman'; font-style: normal; font-variant:
normal; font-weight: normal; letter-spacing: normal; line-height:
normal; orphans: 2; text-indent: 0px; text-transform: none;
white-space: normal; widows: 2; word-spacing: 0px; font-size:
medium;"><span class="Apple-style-span" style="font-family:
arial,helvetica,sans-serif;">fixed_magnetization(i), i=1,3</span></span><br>
<span class="Apple-style-span" style="border-collapse: separate;
color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-style:
normal; font-variant: normal; font-weight: normal; letter-spacing:
normal; line-height: normal; orphans: 2; text-indent: 0px;
text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; font-size: medium;"><span
class="Apple-style-span" style="font-family:
arial,helvetica,sans-serif;"><br>
</span></span>if i used nspin=0, in output file there is still
rho_up and rho_down, does this mean the spin-DFT has already been
considered even nspin=0?<br>
<br>
In my case, I want to perform a cluster calculation with even
electrons. But the cluster may be at triplet state or singlet one. I
just want to switch on the spin-DFT, and let the program determine
which one is the ground state and obtained the stable geometry. So
want should I set?<br>
<br>
Thank you all so much for your help!<br>
<br>
best regards<br>
He jinghui<br>
Department of Chemistry, NUS, singapore<br>
<br>
in may <br>
<br>
<br>
<blockquote cite="mid:mailman.1.1317804548.20558.pw_forum@pwscf.org"
type="cite">
<pre wrap="">Dear Jinghui,
</pre>
<blockquote type="cite">
<pre wrap=""> I was wondering once i set nspin=1, do i have to settot_magnetization?
</pre>
</blockquote>
<pre wrap="">
do you mean "nspin=2"? This is indeed the option for a spin-polarized
(collinear) calculation, see Doc/INPUT_PW.txt
In that case, yes, you have to specify the starting magnetization of the
system (there are a number of ways, again have a look to
Doc/INPUT_PW.txt). And yes, the default is different from SIESTA where
-forbid me, I'm not experienced of that code- imposing "spin_polarized
true" implies by default a ferromagnetic starting point.
HTH,
Guido
PS As for NEB, keep in mind that if the magnetization of your system is
crucially depending on coordinates (as an example, if your transition
state is magnetic but the initial and final states are not), then you
might have some difficulty in imposing the true magnetized state for some
image in the path, because the starting charge density might be
extrapolated from previous steps where the system is not magnetic. In that
case, you could either continue the calculation but restarting from atomic
charges, or replace that charge from one of a separate, controlled SCF
calculation.
</pre>
</blockquote>
<br>
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