Dear Christopher,<br><br><br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
The structure is chosen at random, as I simply wish to test the vc-relax procedure, so I don't expect it to have a particular symmetry, although in general, I am dealing with clusters of low symmetry anyway.<br>
<br></blockquote><br>If you are dealing with clusters, then there is no utility of vc-relax for you.<br><div><br> </div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
My problem is that it makes no sense to me that off diagonal elements can be non-zero, when they are relative. How can one have a value 0.000341145 x 0 (in the case of element (1,2))? This, I do not understand.<br>
<br>
Furthermore, what would a negative relative parameter mean?<br>
I suspect I am misinterpreting the meaning of these alat cell parameter matrices, but I'm not sure how.<br clear="all"></blockquote></div><br>The matrix, you see in the output, is Bravais matrix, i.e. a matrix, where the cartesian coordinates of a<br>
unit cell vectors are packed in rows.<br><br>The notation:<br><br>CELL_PARAMETERS (alat= 30.23000000)<br>
1.003485881 0.000341145 -0.000166335<br>
0.000341140 1.002476151 0.000847099<br>
-0.000166325 0.000846982 1.001936910<br>
<br>means that Bravais matrix is:<br><br>{ 1.003485881 0.000341145 -0.000166335 } <br>
{ 0.000341140 1.002476151 0.000847099 } times alat = <br>
{ -0.000166325 0.000846982 1.001936910 } <br><br>{ 30.3354 0.0103 -0.0050 }<br>{ 0.0103 30.3049 0.0256 }<br>{ -0.0050 0.0256 30.2886 }<br><br>
Hope, it helps.<br><br>-- <br>Best regards, Max Popov<br>Ph.D. student<br>Materials center Leoben (MCL), Leoben, Austria.<br>