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Dear Dr Blaha and Dr Cottenier,<br><br> Thanks for your suggestions. I think I have enough information to get the<br>job done.<br><br><br>Fhokrul<br><br><br>> Date: Thu, 25 Feb 2010 17:44:14 +0100<br>> From: pblaha@theochem.tuwien.ac.at<br>> To: wien@zeus.theochem.tuwien.ac.at<br>> Subject: Re: [Wien] problem with DOS calculations<br>> <br>> I guess we had these questions before.<br>> <br>> The TETRAHEDRON method calculates the DOS band by band.<br>> With one k-point a "band" consists only of ONE energy and thus would give a<br>> delta function. In other words: even if your eigenvalues are at 0.099999 (band 1) and 0.100001<br>> (band 2), the DOS from tetra at 0.10000 is exactly zero (while the integrated DOS (see Stefaans comment)<br>> will increase by 2 electrons for the energies 0.099 and 0.100.<br>> <br>> For one k-point, one needs a "histogramm method", i.e. you should specify an energy mesh (eg. 0.005 Ry),<br>> then take case.energy (or case.qtl) and then simply "count" the eigenvalues in each interval (remember,<br>> the DOS is the number of states/energy intervall). Finally you may smoothen the curve and put some<br>> gauss broadening on it.<br>> <br>> <br>> Stefaan Cottenier schrieb:<br>> > <br>> >> Addendum: you can take the intermediate output, put them into a<br>> >> spreadsheet such as Excel and plot the dos yourself with some<br>> >> broadening -- it works but is not so convenient.<br>> > <br>> > Two comments on this:<br>> > <br>> > 1) you can specify a broadening in case.int (see Sec. 8.1.3 of the UG)<br>> > <br>> > 2) there is a very robust integration of the DOS plotted in <br>> > case.outputt. Even if the energy step is too large to see a spike, it <br>> > will appear clearly as a sudden jump of the integrated value.<br>> > <br>> > Stefaan<br>> > _______________________________________________<br>> > Wien mailing list<br>> > Wien@zeus.theochem.tuwien.ac.at<br>> > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien<br>> <br>> -- <br>> -----------------------------------------<br>> Peter Blaha<br>> Inst. Materials Chemistry, TU Vienna<br>> Getreidemarkt 9, A-1060 Vienna, Austria<br>> Tel: +43-1-5880115671<br>> Fax: +43-1-5880115698<br>> email: pblaha@theochem.tuwien.ac.at<br>> -----------------------------------------<br>> _______________________________________________<br>> Wien mailing list<br>> Wien@zeus.theochem.tuwien.ac.at<br>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien<br> <br /><hr />Hotmail: Free, trusted and rich email service. <a href='https://signup.live.com/signup.aspx?id=60969' target='_new'>Get it now.</a></body>
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