<div dir="auto">Useful notes. One should only use the options for something like a surface, and the method is a bit "Experimental" and not well documented. The next time I look in a mirror I will tell the person who added the incomplete "999" information output to improve that.<div dir="auto"><br></div><div dir="auto">The forces should be correct, years ago they were checked as the energy change of a proton/ion. I don't know of a way to check for a missing constant in the energy.<br><br><div data-smartmail="gmail_signature" dir="auto">---<br>Professor Laurence Marks<br>"Research is to see what everybody else has seen, and to think what nobody else has thought", Albert Szent-Gyorgi<br><a href="http://www.numis.northwestern.edu">http://www.numis.northwestern.edu</a><br>Corrosion in 4D <a href="http://MURI4D.numis.northwestern.edu">http://MURI4D.numis.northwestern.edu</a><br>Partner of the CFW 100% gender equity project, <a href="http://www.cfw.org/100-percent">www.cfw.org/100-percent</a><br>Co-Editor, Acta Cryst A<br> </div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mar 7, 2017 22:15, "Gavin Abo" <<a href="mailto:gsabo@crimson.ua.edu">gsabo@crimson.ua.edu</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div class="m_479453782831603337moz-cite-prefix">Not sure if it helps, but below are notes I have made on the electric field:<br>
------------------------------<wbr>------------------------------<wbr>------------------------------<wbr>--<br>
Use of the electric field seems somewhat undocumented.<br>
<br>
Reference the case.in0 section (7.1.3) in the WIEN2k usersguide [ <a class="m_479453782831603337moz-txt-link-freetext" href="https://urldefense.proofpoint.com/v2/url?u=http-3A__susi.theochem.tuwien.ac.at_reg-5Fuser_textbooks_usersguide.pdf&d=CwMD-g&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=eeKYEMnftGLp2ut0c9RNPvtayAX6L0w5gp9ebwewtSI&s=hunOVhWKc9GBCWcrWxIRS4S-Xrzt0_DzMiPlZfhp_Kc&e=" target="_blank">
http://susi.theochem.tuwien.<wbr>ac.at/reg_user/textbooks/<wbr>usersguide.pdf</a> ].<br>
<br>
There seems to be 13 modes and 2 Fourier options to choose from. To list the modes, add:
<br>
<br>
-999 2<br>
<br>
on line 4 in the case.in0 file, then run in a terminal in the case directory:<br>
<br>
x lapw0<br>
<br>
It should output:<br>
<br>
Available E-field modes<br>
Mode 0 is Analytic triangular ramp <wbr>
<br>
Mode 1 is =0 if |z|<lambda, otherwise E*cos((z0-lambda)*pi2/(0.5-<wbr>lambda))
<br>
Mode 2 is =0 if |Z|<lambda, otherwise E*(1.D0-cos((z0-lambda)*pi2/(<wbr>0.5-lambda)))
<br>
Mode 3 is =0 if |z|<lambda, otherwise E*(1-cos((z0-lambda)*pi/(0.5-<wbr>lambda)))*0.5D0
<br>
Mode 4 is =E if |z|<lambda, otherwise E*(0.5D0-Z0)/(0.5d0-lambda) <wbr>
<br>
Mode 5 is =0 if |z|<lambda, otherwise E*(1.D0-(0.5D0-Z0)/(0.5d0-<wbr>lambda))
<br>
Mode 6 is Form from Lozovoi et al, J. Chem Phys, 115, 1661, 2001, normalized to max of 1
<br>
Mode 7 is Form from Lozovoi et al, J. Chem Phys, 115, 1661, 2001
<br>
Mode 8 is =Constant E <wbr> <wbr>
<br>
Mode 9 is =0 if |z|<lambda, otherwise E <wbr>
<br>
Mode 10 is =E if |z|<lambda, otherwise E*((1-cos((z0-lambda)*pit/cut)<wbr>)*0.5D0)
<br>
Mode 11 is Numerical Triangular ramp from E/2 to -E/2 <wbr>
<br>
Mode 12 is Numerical Triangular ramp from 0 to -E <wbr>
<br>
Add 20 for finite Fourier series<br>
Add 40 for Fourier expansion within RMTs<br>
<br>
Note: The above list isn't fully displayed when x lapw0 is ran in w2web, so use a terminal instead of w2web.<br>
<br>
According to the post<br>
<br>
<a class="m_479453782831603337moz-txt-link-freetext" href="https://urldefense.proofpoint.com/v2/url?u=http-3A__zeus.theochem.tuwien.ac.at_pipermail_wien_2008-2DMay_010928.html&d=CwMD-g&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=eeKYEMnftGLp2ut0c9RNPvtayAX6L0w5gp9ebwewtSI&s=1Azt3QgtYKxnYQv7WdNzZXP74krK6hibZqO-aXocyt8&e=" target="_blank">http://zeus.theochem.tuwien.<wbr>ac.at/pipermail/wien/2008-May/<wbr>010928.html</a><br>
<br>
run a typically scf cycle to convergence without the electric field (line 4 blank in case.in0).<br>
<br>
Then, add the electric field. For example, if "Mode 8 is =Constant E" is chosen with an amplitude of 5 Ry, then line 4 of case.in0 would be<br>
<br>
8000 5<br>
<br>
where Mode = IEFIELD/1000 = 8000/1000 = 8<br>
<br>
If a value of lambda of say 3 is specified such as for Mode 1, then add it as a third column value to line 4 of case.in0:<br>
<br>
1000 5 3<br>
<br>
Then, run x lapw0 or another scf cycle for the electric field.<br>
<br>
I don't know if a supercell needs to be used for all or just some of the potentials. Could try asking the mailing list. Also, refer to the posts:<br>
<br>
<a class="m_479453782831603337moz-txt-link-freetext" href="https://urldefense.proofpoint.com/v2/url?u=http-3A__zeus.theochem.tuwien.ac.at_pipermail_wien_2011-2DJune_014946.html&d=CwMD-g&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=eeKYEMnftGLp2ut0c9RNPvtayAX6L0w5gp9ebwewtSI&s=_Rbm4Iu1zY3YBG7AOzhMYo3UfyT01Ji3v318ZWESNp8&e=" target="_blank">http://zeus.theochem.tuwien.<wbr>ac.at/pipermail/wien/2011-<wbr>June/014946.html</a><br>
<a class="m_479453782831603337moz-txt-link-freetext" href="https://urldefense.proofpoint.com/v2/url?u=http-3A__zeus.theochem.tuwien.ac.at_pipermail_wien_2004-2DSeptember_003549.html&d=CwMD-g&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=eeKYEMnftGLp2ut0c9RNPvtayAX6L0w5gp9ebwewtSI&s=W7j7HOJhjXEIPGSNEPJ_l-2AGqkcZF0yogWBaNupYZU&e=" target="_blank">http://zeus.theochem.tuwien.<wbr>ac.at/pipermail/wien/2004-<wbr>September/003549.html</a><br>
<a class="m_479453782831603337moz-txt-link-freetext" href="https://urldefense.proofpoint.com/v2/url?u=http-3A__zeus.theochem.tuwien.ac.at_pipermail_wien_2008-2DSeptember_011449.html&d=CwMD-g&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=eeKYEMnftGLp2ut0c9RNPvtayAX6L0w5gp9ebwewtSI&s=85n5Eq-7FCG0AZt-W2-JZnIcp1e2ilw93-FawCKED2s&e=" target="_blank">http://zeus.theochem.tuwien.<wbr>ac.at/pipermail/wien/2008-<wbr>September/011449.html</a><br>
<a class="m_479453782831603337moz-txt-link-freetext" href="https://urldefense.proofpoint.com/v2/url?u=http-3A__zeus.theochem.tuwien.ac.at_pipermail_wien_2008-2DSeptember_011340.html&d=CwMD-g&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=eeKYEMnftGLp2ut0c9RNPvtayAX6L0w5gp9ebwewtSI&s=u4FFv8oeGkd943JodFfp2V0tq7nEuU5RcyGKPIYeikE&e=" target="_blank">http://zeus.theochem.tuwien.<wbr>ac.at/pipermail/wien/2008-<wbr>September/011340.html</a><br>
<br>
E-field source code: SRC_lapw0/epot1.f<br>
------------------------------<wbr>------------------------------<wbr>------------------------------<wbr>--<br>
<br>
As a quick test only, I put "120 -0.50" in line 4 of TiC.in0 and ran x lapw0. The output in TiC.scf0 suggests the 120 gives a triangular ramp electric field with 120 Fourier coefficients, and it also sets an amplitude of -0.5 Ry. So I'm wondering if the behavior
seen in the difference observed between structures A & B has anything to due with how the triangular ramps have been positioned in those two structures.<br>
<br>
username@computername:~/<wbr>wiendata/TiC$ grep :EFIELD *.scf0<br>
:EFIELD E-field of -0.50000 Ry with 120 Fourier coefficients requested<br>
:EFIELD Form is Analytic triangular ramp <wbr>
<br>
:EFIELD Number of FC in E-field 8 , Largest 14<br>
<br>
On 3/7/2017 8:59 AM, Laurence Marks wrote:<br>
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<div dir="ltr">I probably should know/remember the answer to this question, but I don't.
<div><br>
</div>
<div>In lapw0 we can add an electric field, is the energy right or not? </div>
<div><br>
</div>
<div>For reference, I have two different structures A & B and I want to compare the change in energy between the two in a field. The difference is opposite to what I expected, so either my expectation is wrong or an energy term is missing. For reference, I
have added "120 -0.50" at the bottom of case.in0 and I am minimizing the positions/forces (which I seem to remember were right but that does not prove that a constant is not missing). Uncharged unit cell.</div>
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<div dir="ltr"><span style="font-size:12.8px">Professor Laurence Marks</span><br>
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<div dir="ltr"><span style="font-size:12.8px">"Research is to see what everybody else has seen, and to think what nobody else has thought", </span><span style="font-size:12.8px">Albert Szent-Gyorgi</span><br>
<a href="http://www.numis.northwestern.edu" target="_blank">www.numis.northwestern.edu</a> ; <span style="font-size:12.8px">C<wbr>orrosion in 4D:
</span><a href="http://MURI4D.numis.northwestern.edu" style="font-size:12.8px" target="_blank">MURI4D.numis.northwestern.edu</a>
<div><span style="font-size:12.8px">Partner of the CFW 100% program for gender equity, </span><a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__www.cfw.org_100-2Dpercent&d=CwMD-g&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=eeKYEMnftGLp2ut0c9RNPvtayAX6L0w5gp9ebwewtSI&s=Nr4_h2YSvj7mBiMfRqW0WLUqZs68s-Wj4xIyvu9N7KE&e=" style="font-size:12.8px" target="_blank">www.cfw.org/100-<wbr>percent</a></div>
<div>Co-Editor, Acta Cryst A</div>
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