<div>Dear Nicola,</div>
<div> </div>
<div> Thank you.</div>
<div>I do want to repeat Prof Postermak's works on tio2.</div>
<div>Last night, i also tried to change projection functions for rutile tio2. Indeed, i also found there </div>
<div>are 2 more minimum spreads founded with different stating projection functions.</div>
<div> </div>
<div>For rutile case, when i started with s/px/py/pz on O sites, i obtained total spreads of 14.919. while changing projection functions to sp2/pz on O sites, i obtained total spreads of 14.4672. But wannier function centers can both be classified into 4 groups.
</div>
<div> </div>
<div>Regards,</div>
<div> </div>
<div>Hai-Ping</div>
<div> </div>
<div><br> </div>
<div><span class="gmail_quote">On 12/18/06, <b class="gmail_sendername">Nicola Marzari</b> <<a onclick="return top.js.OpenExtLink(window,event,this)" href="mailto:marzari@mit.edu" target="_blank">marzari@mit.edu</a>> wrote:
</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid"><br><br>Dear Hai-Ping,<br><br><br>I believe Michel Posternak has published a paper on Ti02 Wannier<br>functions. It would be interesting to compare your results to his.
<br><br>Our consensus was that the localization functional can display<br>minima that are not meaningful - usually marked by the fact that the<br>MLWFs do not look localized, or symmetric, and especially that they are<br>
not real-valued, but are complex-valued. These incorrect minima are<br>somewhat connected to the fact that there are few points in the BZ where<br>a smooth continuous choice of phase factors was not achieved.<br><br>There are cases when more than one good minimum can exist - the first
<br>one that comes to my mind is benzene, where you can have two equivalent<br>choices for the location of the three double bonds on the aromatic ring.<br><br>It could be that yours is another case - there is more that one
<br>meanigful minimum - and, the notion of "meaningful minimum" is rather<br>heuristic.<br><br>Let us know what you find,<br><br> nicola<br><br><br><br><br>lan haiping wrote:<br>> Dear All,
<br>><br>> I came to confusion about final results of wannierise procedure.<br>> I am trying to analyse anatase tio2 wannier function and born charge<br>> with wannier90.x.<br>> I performed 2 calculations with 2 different projection functions sets,
<br>> other settings are same. Both reached convergenc (error deltas for total<br>> Omega are about 1E-10). But the total spreads and wannier centers are<br>> quite different.<br>> For my first calculation, i just start with sp2 and pz functions at O
<br>> sites, the total spreads finally obtained is 14.397.<br>> While for the second calculation, the projetion functions are s/px/py/pz<br>> functions at O sites, the total spreads finally obtained is then<br>>
15.2170.<br>><br>> The wannier functions of second calculation could be classed into 4<br>> groups by spreads , while the conclusion is not hold for the fist<br>> calculation ( the wannier functions are then classed into 8 groups ).
<br>><br>> According to MV paper, the MLWFs reflect structures' symmetry by<br>> spreads. So, Both 2 calculations are not correct.<br>><br>> Would you please give me some comments ?<br>> And input files are below :
<br>><br>> *num_wann = 16<br>> num_iter = 2000<br>> guiding_centres = T<br>> exclude_bands = 1 2 3 4 5 6 7 8 25 26 27 28 29 30<br>> begin projections<br>> O : sp2<br>> O : pz<br>> end projections
<br>> begin atoms_cart<br>> Ti 0.000000000 -0.000000000 0.000000000<br>> Ti 0.000000000 1.892500000 2.378500000<br>> O 0.000000000 0.000000000 1.979863400<br>> O 0.000000000
-0.000000000 7.534136600<br>> O 0.000000000 1.892500000 4.358363400<br>> O 0.000000000 1.892500000 0.398636600<br>> end atoms_cart*<br>><br>> *begin unit_cell_cart<br>> Ang<br>
> 1.8925 -1.8925 4.757<br>> 1.8925 1.8925 4.757<br>> -1.8925 -1.8925 4.757<br>> end unit_cell_cart<br>> mp_grid : 6 6 6<br>> begin kpoints<br>> ......<br>> end kpoints*<br>><br>> two final spreads and wannier centers are attached.
<br>><br>> *Regards*<br>><br>> Hai-Ping<br>><br>><br>><br>> --<br>> Hai-Ping Lan<br>> Department of Electronics ,<br>> Peking University , Bejing, 100871<br>><br>><br>> ------------------------------------------------------------------------
<br>><br>> Final State<br>> WF centre and spread 1 ( -0.057359, 0.368438, 2.144012 ) 0.81913203<br>> WF centre and spread 2 ( -0.057359, -0.368438, 2.144012 ) 0.81913201<br>> WF centre and spread 3 (
0.207447, 0.000000, 1.889906 ) 1.06292459<br>> WF centre and spread 4 ( -0.197679, 0.225730, 7.480939 ) 0.95045581<br>> WF centre and spread 5 ( -0.197683, -0.225729, 7.480937 ) 0.95045348
<br>> WF centre and spread 6 ( 0.383935, 0.000000, 7.384053 ) 0.82485652<br>> WF centre and spread 7 ( -0.197693, 2.118226, 4.411569 ) 0.95044526<br>> WF centre and spread 8 ( -0.197669
, 1.666767, 4.411555 ) 0.95046140<br>> WF centre and spread 9 ( 0.383935, 1.892503, 4.508447 ) 0.82485530<br>> WF centre and spread 10 ( -0.057359, 2.260938, 0.234488 ) 0.81913205<br>> WF centre and spread 11 ( -
0.057359, 1.524062, 0.234488 ) 0.81913192<br>> WF centre and spread 12 ( 0.207447, 1.892500, 0.488594 ) 1.06292460<br>> WF centre and spread 13 ( -0.090800, 0.000000, 1.575406 ) 0.88848488
<br>> WF centre and spread 14 ( 0.012349, 0.000000, 7.957177 ) 0.88317336<br>> WF centre and spread 15 ( 0.012349, 1.892503, 3.935322 ) 0.88317159<br>> WF centre and spread 16 ( -0.090800
, 1.892500, 0.803094 ) 0.88848495<br>> Sum of centres and spreads ( 0.005703, 15.139999, 57.083998 ) 14.39721976<br>><br>><br>> ------------------------------------------------------------------------
<br>><br>> Final State<br>> WF centre and spread 1 ( 0.000000, 0.000000, 1.913455 ) 1.16247952<br>> WF centre and spread 2 ( 0.000000, 0.000000, 7.509543 ) 1.20049037<br>> WF centre and spread 3 (
0.000000, 1.892500, 4.382956 ) 1.20048903<br>> WF centre and spread 4 ( 0.000000, 1.892500, 0.465045 ) 1.16247952<br>> WF centre and spread 5 ( 0.000000, 0.000000, 2.004457 ) 1.20048828
<br>> WF centre and spread 6 ( 0.000000, 0.000000, 7.600545 ) 1.16248168<br>> WF centre and spread 7 ( 0.000000, 1.892500, 4.291955 ) 1.16248025<br>> WF centre and spread 8 ( 0.000000
, 1.892497, 0.374043 ) 1.20048827<br>> WF centre and spread 9 ( 0.000000, 0.000000, 1.522196 ) 0.75151445<br>> WF centre and spread 10 ( 0.000000, 0.000000, 7.991803 ) 0.75151691<br>> WF centre and spread 11 (
0.000000, 1.892500, 3.900696 ) 0.75151511<br>> WF centre and spread 12 ( 0.000000, 1.892501, 0.856304 ) 0.75151453<br>> WF centre and spread 13 ( 0.000000, 0.000000, 2.312422 ) 0.68819033
<br>> WF centre and spread 14 ( 0.000000, 0.000000, 7.201578 ) 0.68819219<br>> WF centre and spread 15 ( 0.000000, 1.892500, 4.690922 ) 0.68819114<br>> WF centre and spread 16 ( 0.000000
, 1.892502, 0.066078 ) 0.68819026<br>> Sum of centres and spreads ( 0.000000, 15.139999, 57.083998 ) 15.21070184<br><br><br>--<br>---------------------------------------------------------------------<br>Prof Nicola Marzari Department of Materials Science and Engineering
<br>13-5066 MIT 77 Massachusetts Avenue Cambridge MA 02139-4307 USA<br>tel 617.4522758 fax 2586534 <a onclick="return top.js.OpenExtLink(window,event,this)" href="mailto:marzari@mit.edu" target="_blank">marzari@mit.edu
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http://www.democritos.it/mailman/listinfo/wannier</a><br></blockquote></div><br><br clear="all"><br>-- <br>Hai-Ping Lan <br>Department of Electronics ,<br>Peking University , Bejing, 100871