Dear, haiping<br><br>I'll check it, thank you for your help.<br><br>would you please add to QQ group which is composed of many PWSCF users or similar code, such as CASTEP, VASP or DACAPO. The No. is 35451926. We could discuss the code or the scientific problem more convenient with PH. D. student in Chinese.<br>
<br>thank you again<br><br>vega<br><br><div class="gmail_quote">On Sun, Mar 1, 2009 at 8:20 PM, lan haiping <span dir="ltr"><<a href="mailto:lanhaiping@gmail.com">lanhaiping@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi, Weijia,<br>In fact, you can have a look at mix_rho.f90 for detailed agorithms used <br>in QE package for density mixing scheme .<br>The scheme is just modified Broyden's method for charge density mixing<br>, please see D.D. Johnson PRB 38, 12807 (1988).<br>
<br><br>regards,<div><div></div><div class="Wj3C7c"><br><br><br><div class="gmail_quote">On Sun, Mar 1, 2009 at 8:09 PM, vega lew <span dir="ltr"><<a href="mailto:quantumdft@gmail.com" target="_blank">quantumdft@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Dear friend,<br><br>I found there is few supporting materials decribing what the exact meaning for mixing_beta. do you think the following paragraph from the manual of Materials Studio is suitable for this parameters?<br>
<br>
------------------------------------------------<br><p><span>Electronic minimizer: </span>Specify the electronic
minimization method to be used for the SCF calculation. Two options are
available, <span>Density Mixing</span> and <span>All
Bands/EDFT</span>.</p>
<p><span>Tip. </span>The <span>Density
Mixing </span>option is recommended, particularly for variable occupancy
calculations. The <span>All Bands/EDFT</span> method is usually
slower and requires more memory. However, the EDFT scheme is recommended for
metallic systems where converging electronic structure using <span>Density Mixing</span> option proves problematic.</p>
<p><span>Charge: </span>Specify the amplitude for charge density
mixing (i.e., the amplitude of the output charge density to mix with the input
charge density to obtain input for the next iteration). </p>
<p><span>Note. </span>This option is enabled only if
the <span>Density Mixing </span>minimization method is selected.
</p>
<p><span>Spin: </span>Specify the amplitude for spin density
mixing, i.e. the amplitude of the output spin density to mix with the input spin
density to obtain input for the next iteration. </p>
<p><span>Note. </span>This option in enabled only for
spin-polarized calculations using the <span>Density Mixing</span>
minimization method. <br></p><p>-------------------------------------------------</p><p>Shoul I consider the mixing_mode option in PWSCF is equal to <span>Density
Mixing </span>option in MS, and value of mixing_bate in PWSCF is equal to the one of <span>Charge in MS</span>? <br></p><p>Do you think I should swich on the boardening by 'occupations', 'degauss' and 'smearing' command in PWSCF?</p>
<p>I also found no detail description for this three options.</p><p>do you think the following text suitable for the three command in PWSCF?</p><p>-----------------------------</p><p>
</p><p><span>Smearing: </span>Specify the broadening to be applied to
the electronic occupation. </p>
<p><span>Note. </span>This option is enabled only for
variable occupancy calculations. <br></p><p>-----------------------------</p><p>If the answer is no, could you please give me some suggestion to understanding the command and make a better use of it.</p>
<p>thank you so much for reading</p><p><br>best wishes,</p><p>vega<font color="#888888"><br></font></p><div><div></div><div><p><br></p><p><br></p><p></p><div class="gmail_quote">On Sun, Mar 1, 2009 at 7:44 PM, vega lew <span dir="ltr"><<a href="mailto:quantumdft@gmail.com" target="_blank">quantumdft@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Dear APSI<br><br>thank you for you suggestions to me.<br><br>I will try it ASAP.<br><br>vega<br>
<br><div class="gmail_quote"><div><div></div><div>On Sun, Mar 1, 2009 at 5:08 PM, Ari Paavo Seitsonen <span dir="ltr"><<a href="mailto:ari.p.seitsonen@iki.fi" target="_blank">ari.p.seitsonen@iki.fi</a>></span> wrote:<br>
</div></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><div></div><div><br>
Dear Vega,<br>
<br>
Just my guesses and suggestions: One could try mixing of the density, like<br>
<br>
&electrons<br>
mixing_beta = 0.7<br>
/<br>
<br>
(or a value even smaller than 0.7, or some other parametres for the mixing) since with a defect you might now have defect levels in the band gap, leading to a more difficult a convergence. Eventually one could also switch on the broadening of the occupation numbers, eventually switching it off for the physical/production jobs, but just to check if the problem in convergence comes due to this.<br>
<br>
And in the original paper the authors discuss spin-polarisation, one might test also this (nspin = 2), with different initial magnetisations [starting_magnetization(xx) = ...] for the atoms surrounding the defect.<br>
<br>
Greetings,<br>
<br>
apsi<div><br>
<br>
<br>
On Sun, 1 Mar 2009, vega lew wrote:<br>
<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Dear all,<br>
<br>
I am planning to calculate the Oxygen vacancy properties of TiO2 surfaces.<br>
The calculation for the ideal surfaces are quite normal and the results are<br>
in line with the one that literature reported. But, when I tried to<br>
calculate the anatase 101 surface with an Oxygen vacancy (O2c was removed<br>
directly from the stoichiometric Anatase 101as described in J. Phys. Chem. C<br>
2007, 111, 16397-16404, I encounter the problem of convergence for SCF<br>
cycle. I tried to add 20% more empty band to the system the problem still<br>
laid in. How could I overcome the problem?<br>
<br>
my input file was attached at the bottom of the mail<br>
<br>
thank you for reading. Any hints will be appreciated.<br>
<br>
vega<br>
<br>
</blockquote>
<br></div>
...<div><div></div><div><br>
<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<br>
&SYSTEM<br>
ibrav = 8,<br>
celldm(1) =19.3269,<br>
celldm(2) = 1.1094,<br>
celldm(3) = 1.7450,<br>
nat = 71,<br>
ntyp = 2,<br>
nosym = .true.,<br>
ecutwfc = 30,<br>
ecutrho = 300,<br>
/<br>
<br>
&ELECTRONS<br>
<br>
/<br>
<br>
&IONS<br>
ion_dynamics = 'bfgs',<br>
/<br>
<br>
</blockquote>
<br></div></div><font color="#888888">
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-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-<br>
Ari P Seitsonen / <a href="mailto:Ari.P.Seitsonen@iki.fi" target="_blank">Ari.P.Seitsonen@iki.fi</a> / <a href="http://www.iki.fi/%7Eapsi/" target="_blank">http://www.iki.fi/~apsi/</a><br>
IMPMC, CNRS & Université Pierre et Marie Curie<br>
Tel: +33-1-4427 7542, Fax: +33-1-4427 3785, GSM: +33-6-6736 3820</font><br></div></div>_______________________________________________<br>
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<br></blockquote></div><div><div></div><div><br><br clear="all"><br>-- <br>==================================================================================<br>Vega Lew ( weijia liu)<br>PH.D Candidate in Chemical Engineering<br>
State Key Laboratory of Materials-oriented Chemical Engineering<br>
College of Chemistry and Chemical Engineering<br>Nanjing University of Technology, 210009, Nanjing, Jiangsu, China<br>******************************************************************************************************************<br>
Email: <a href="mailto:vegalew@gmail.com" target="_blank">vegalew@gmail.com</a><br>Office: Room A705, Technical Innovation Building, Xinmofan Road 5#, Nanjing, Jiangsu, China <br>****************************************************************************************************************** <br>
</div></div></blockquote></div><br><br clear="all"><br>-- <br>==================================================================================<br>Vega Lew ( weijia liu)<br>PH.D Candidate in Chemical Engineering<br>State Key Laboratory of Materials-oriented Chemical Engineering<br>
College of Chemistry and Chemical Engineering<br>Nanjing University of Technology, 210009, Nanjing, Jiangsu, China<br>******************************************************************************************************************<br>
Email: <a href="mailto:vegalew@gmail.com" target="_blank">vegalew@gmail.com</a><br>Office: Room A705, Technical Innovation Building, Xinmofan Road 5#, Nanjing, Jiangsu, China <br>****************************************************************************************************************** <br>
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<br></blockquote></div><br><br clear="all"><br>-- <br></div></div>Hai-Ping Lan <br>Department of Electronics ,<br>Peking University , Bejing, 100871<br><a href="mailto:lanhaiping@gmail.com" target="_blank">lanhaiping@gmail.com</a>, <a href="mailto:hplan@pku.edu.cn" target="_blank">hplan@pku.edu.cn</a><br>
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<br></blockquote></div><br><br clear="all"><br>-- <br>==================================================================================<br>Vega Lew ( weijia liu)<br>PH.D Candidate in Chemical Engineering<br>State Key Laboratory of Materials-oriented Chemical Engineering<br>
College of Chemistry and Chemical Engineering<br>Nanjing University of Technology, 210009, Nanjing, Jiangsu, China<br>******************************************************************************************************************<br>
Email: <a href="mailto:vegalew@gmail.com">vegalew@gmail.com</a><br>Office: Room A705, Technical Innovation Building, Xinmofan Road 5#, Nanjing, Jiangsu, China <br>****************************************************************************************************************** <br>