<div>Dear Prof Nicola Marzari:</div>
<div>thank you for your help , i am really grateful i will read the paper and book you have recommended to me.</div>
<div>if there is some question about the paper i would like to consult with you .Hope get your help .</div>
<div> Xu Yuehua</div>
<div> 07.05.22<br><br> </div>
<div><span class="gmail_quote">2007/5/22, Nicola Marzari <<a href="mailto:marzari@mit.edu">marzari@mit.edu</a>>:</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">xu yuehua wrote:<br>> yes,before pho calculation ,i have computed "scf" .the water. in is this
<br>> &system<br>> ibrav = 0,<br>> nat = 15,<br>> ntyp = 2,<br>> ecutwfc = 29.98744D0,<br>> ecutrho =200<br>> occupations = "smearing",<br>> smearing = "gauss",
<br>> degauss = 0.003D0,<br>> if it is unsuitable ,i have no idea to use what occupations and so on<br>> .please help me .thanks<br><br><br><br>> my name is xu yuehua<br>> affilation: physics depatment
<br>> nanjing university china.<br><br>Dear Xu,<br><br>welcome to the gang.<br><br>There are two comments to make here - if you want your calculation to<br>work, start by droppping the keywords for occupations, smearing, and
<br>degauss. Those three are used for systems with fractional occupations -<br>these are typically metals, and that's why phonon stopped. By the<br>way, "Phonon" calculation for the water molecule and the water dimer
<br>are available in a 2005 JCP by Sit and Marzari - you could compare your<br>results and parameters with those.<br><br>The second comment is that even completing your calculations<br>successfully won't be very helpful, if you do not first become
<br>experienced in this kind of calculations.<br><br>Now, I'm not sure what to suggest - there is a book on "Electronic<br>Structure" by Richard Martin that is outstanding, but a bit advanced.<br>A more introductory one has recently come out, by Jorge Kohanoff
<br>("Electronic Structure Calculations for Solids and Molecules).<br><br>I might sound self-serving, but our graduate class on atomistic<br>modeling of materials (including video lectures, and pwscf homework),<br>is fully on the web, linked from
<br><a href="http://quasiamore.mit.edu/pmwiki/index.php?n=Main.Teaching">http://quasiamore.mit.edu/pmwiki/index.php?n=Main.Teaching</a> ).<br>This class takes MIT students of different backgrounds, and that<br>have never seen computational modeling, through a basic knowledge
<br>of the fundamentals.<br><br> nicola<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 href="mailto:marzari@mit.edu">marzari@mit.edu</a> <a href="http://quasiamore.mit.edu">http://quasiamore.mit.edu</a>
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</a><br></blockquote></div><br><br clear="all"><br>-- <br>Xu Yuehua<br>physics Department of Nanjing university<br>China