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<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>Dear experts in calculations of electronic structure of solids by means
of Wien2K,</FONT></P>
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face="Times New Roman"> <?xml:namespace prefix = o ns =
"urn:schemas-microsoft-com:office:office" /><o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>I am trying to start Wien2K calculations on conjugated organic molecules
and I chose isolated molecules of benzene C6H6 to start with, because I thought
it would be a technically simple case, good for beginners.</FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><FONT
face="Times New Roman"> <o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>I have tried to rerun the examples (TiC, TiO2) enclosed to the software –
it worked, with small troubles, though. </FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><FONT
face="Times New Roman"> <o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>I am asking you for an advice or a critical comment on a procedure I used
to run the calculations on benzene, which have not led me further than “dstart”
within the initialization of the calculations, reporting an error. </FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><FONT
face="Times New Roman"> <o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>I will describe my input to the calculation procedure below and in the
.htm and .gif file attached.</FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>-Isolated molecules of benzene – Alexei>>W2K-</FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>I supposed the unit cell to be cubic with 15 Angstr side length - to make
sure the distance between adjacent molecules is long enough.</FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>I used conventional literature data on the relevant bond lengths and
angles (detailes are attached)</FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>I used 1.2 and 0.6 RMT for C and H respectively. </FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>I typed the necessary positions of the 12 inequivalent atoms as the
fractions of the unit cell. </FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>--With this the programs “sgroup” and “symmetry” did not agree: they
suggested to make 6 couples of inequivalent atoms so as to couple the left and
the right sides of benzene molecule (according to the figure in the attachment),
the programs suggested that I, in fact, had a lattice type 6_m_m, - I tried both
to accept and not to accept that, and as soon as I accepted it they suggested a
change again (that the lattice type should actually be 25_(p_m) or so). As soon
as I accepted these symmetries – “lstart” would indicate inconsistency with
Z-atomic number. </FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>I also checked the cell composition as 6 equivalent carbons and 6
equivalent hydrogens. </FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>I also tried to introduce distortions to the structure as manually typing
5-10% misplacements in the atom positions. </FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>I also tried to type different indexes to the atoms.</FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>In any case “dstart” would give an error with no diagnostics or an error:
ROTDEF – (no symmetry found)</FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><FONT
face="Times New Roman"> <o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>Please write me a few words with a clue or a comment on what was wrong
with my approach. </FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><FONT
face="Times New Roman"> <o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>Thank you in advance for your time</FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>Alexei Komolov</FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"
size=3>St.Petersburg State University</FONT></P></FONT></DIV></BODY></HTML>