<div dir="ltr">Dear Moses, <div><br></div><div>there is not actually a universal recipe and the means used depends on your feeling. I'm not an expert about Burai. As far as XCrysDen is concerned, I use it a lot to visualize the structure, not to build it.</div><div><br></div><div>Personally, I've always found it instructive try, to the best of what I can do, to build structures "by hand", because this is in my opinion the best way to "enter a crystal" and know how it is done!<br><br>Few general hints, whatever tool you use:<br>1) first identify the direction of the surface, e.g. 100, 110, 111, ...</div><div>2) identify the "in-plane" lattice vectors. This can coincide with those of the bulk lattice or not. For example, should you want to build the 001 surface of a simple cubic crystal, the 1x1 surface will have a1 = (a,0,0) and a2 = (0,a,0) as surface in-plane vectors</div><div>3) as a corollary of point two there are cases where complex reconstructions (e.g. 2x2, sqrt(3) x sqrt(3), ....) might occur. In these cases, there are the "simplest" systems where you should just take the in-plane vectors of the 1x1 surface unit cell and double, triple, .... them. The trickiest cases are instead when the in-plane vectors of the reconstructed surface ar not only scaled but also rotated with respect to the starting ones.</div><div>4) build, according to the chosen a1 and a2, slab models consisting of n planes, obtained as a periodic repetition of the first plane along the 3d direction. <br>5) take the resulting thickness in the correct units, and add the vacuum in the same units, this will be the length of the 3d vector.</div><div><br></div><div>Be careful: sometimes one has coordinates in Ang, other times in 2 pi / a units, other times in crystal units. It is important that one makes the new coordinates consistent with the units used for the surface. </div><div><br></div><div>Imagine, for example, that you have a simple cubic system with one atom in the unit cell at (0,0,0) and lattice constant a. A 4-slab model will have a unit cell with atoms at<br>(0,0,0)<br>(0,0,a)<br>(0,0,2a)<br>(0,0,3a)<br>The in-plane lattice vectors will be (a,0,0) and (0,a,0). The lattice vector orthogonal to the surface will be (0,0,c) where c = 3a + vacuum space.<br><br>Always visualize your new structure before running any calculation!<br><br>More specific help could be provided for specific structures.</div><div>Giovanni</div><div><br clear="all"><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><span style="color:rgb(0,0,0)">-- <br><br>Giovanni Cantele, PhD<br>CNR-SPIN<br>c/o Dipartimento di Fisica<br>Universita' di Napoli "Federico II"<br>Complesso Universitario M. S. Angelo - Ed. 6<br>Via Cintia, I-80126, Napoli, Italy<br><a href="mailto:giovanni.cantele@spin.cnr.it" style="color:rgb(17,85,204)" target="_blank">e-mail: giovanni.cantele@spin.cnr.it</a><br>Phone: +39 081 676910<br>Skype contact: giocan74<br><br>ResearcherID: <a href="http://www.researcherid.com/rid/A-1951-2009" style="color:rgb(17,85,204)" target="_blank">http://www.researcherid.com/rid/A-1951-2009</a><br>Web page: </span><a href="https://sites.google.com/view/giovanni-cantele/home" style="color:rgb(17,85,204)" target="_blank">https://sites.google.com/view/giovanni-cantele/home</a><br></div></div></div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Il giorno lun 8 apr 2024 alle ore 17:26 MOSES NTSIFUL <<a href="mailto:moses.ntsiful001@stu.ucc.edu.gh">moses.ntsiful001@stu.ucc.edu.gh</a>> ha scritto:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">
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<p align="left" style="margin-bottom:0in;font-weight:normal;line-height:115%;background:transparent">
<font color="#000000"><tt style="font-family:"Liberation Mono",monospace"><font face="Lato"><font size="3" style="font-size:12pt"><span style="text-decoration:none">Dear
</span></font></font></tt><tt style="font-family:"Liberation Mono",monospace"><font face="Lato"><font size="3" style="font-size:12pt"><span style="text-decoration:none">All,</span></font></font></tt></font></p>
<p align="left" style="margin-bottom:0in;font-weight:normal;line-height:115%;background:transparent">
<font color="#000000"><tt style="font-family:"Liberation Mono",monospace"><font face="Lato"><font size="3" style="font-size:12pt"><span style="text-decoration:none">I
hope this email find</span></font></font></tt><tt style="font-family:"Liberation Mono",monospace"><font face="Lato"><font size="3" style="font-size:12pt"><span style="text-decoration:none">s</span></font></font></tt><tt style="font-family:"Liberation Mono",monospace"><font face="Lato"><font size="3" style="font-size:12pt"><span style="text-decoration:none">
you well. I am writing to request your assistance with a specific
task related to crystal structure visualization and manipulation. I
am currently working on a project that requires the creation of a 2 ×
2 × 3 surface of a crystal structure with a 10 Å vacuum using
either Burai or XCrysDen. Despite my efforts, I have not been able to
successfully complete this task. </span></font></font></tt></font>
</p>
<p align="left" style="margin-bottom:0in;font-weight:normal;line-height:115%;background:transparent">
<font color="#000000"><tt style="font-family:"Liberation Mono",monospace"><font face="Lato"><font size="3" style="font-size:12pt"><span style="text-decoration:none">I
was wondering if I could be provided with some guidance on how to proceed.
Specifically, I would appreciate any insights you might have on: </span></font></font></tt></font>
</p>
<ol><li><p align="left" style="margin-bottom:0in;line-height:115%;text-decoration:none;background:transparent">
<font face="Lato"><font size="3" style="font-size:12pt">How to
create a 2 × 2 × 3 surface of a crystal structure in Burai or
XCrysDen. </font></font>
</p>
</li><li><p align="left" style="margin-bottom:0in;line-height:115%;text-decoration:none;background:transparent">
<font face="Lato"><font size="3" style="font-size:12pt">How to
ensure that the resulting surface has a 10 Å vacuum. </font></font>
</p>
</li></ol>
<p align="left" style="line-height:115%;margin-bottom:0.1in;background:transparent"><span style="text-decoration:none">
<font face="Lato"><font size="3" style="font-size:12pt">Thank you in
advance for the assistance. I look forward to hearing from
you soon. </font></font></span>
</p>
<p align="left" style="line-height:115%;margin-bottom:0.1in;background:transparent"><br>
<br>
</p>
<p align="left" style="line-height:115%;margin-bottom:0.1in;background:transparent"><font face="Lato"><font size="3" style="font-size:12pt"><span style="text-decoration:none">Best
regards,</span></font></font></p>
<p align="left" style="line-height:115%;margin-bottom:0.1in;background:transparent"><font face="Lato"><font size="3" style="font-size:12pt"><span style="text-decoration:none">Moses
Ntsiful</span></font></font></p>
</div>
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