[pstricks] Help with electron dots around atoms

[Herbert Voss]

rossi at york.cuny.edu wrote:

> I am trying to place electron dots around an atom.  The atom will then be used
> in xymtex to draw a large molecule.
> 
> Can some one help me to place the electrons around an atom in an unequivocal
> way?
> 
> For the code below, numbers 1 and 2 are OK because the left side and right side
> electrons are put around the atom separately. 
> 
> But number 3 is bad because the left and right electrons are placed at the same
> time, and the origin is shifted.
> 
> Numbers 4, 5, and 6 are really bad.  
> 
> Is there a way to do this so the electrons are placed in an invariant manner?

use always pstricks

Herbert

\documentclass[a4paper,12pt]{article}
\usepackage{pstricks}
\usepackage{pst-node}
\usepackage{pst-slpe}           % CTAN:graphics/pstricks/contrib/pst-slpe
\newsavebox\PBox
\def\TwoDots#1#2{%
   \sbox\PBox{#1}%
   \begin{pspicture}(\wd\PBox,\ht\PBox)
     \rput[lb](0,0){#1}
     \psset{dotsize=2pt, linecolor=black}
     \ifcase#2
       \psdots(1.1\wd\PBox,0.35\ht\PBox)(1.1\wd\PBox,0.65\ht\PBox)%r
     \or\psdots(-0.05,0.35\ht\PBox)(-0.05,0.66\ht\PBox)%l
     \or\psdots(0.35\wd\PBox,-0.1)(0.65\wd\PBox,-0.1)%b
     \or\psdots(0.35\wd\PBox,1.2\ht\PBox)(0.65\wd\PBox,1.2\ht\PBox)%t
     \or\psdots(1.1\wd\PBox,0.15)(1.1\wd\PBox,0.30)%r
        \psdots(-0.05,0.35\ht\PBox)(-0.05,0.65\ht\PBox)%l
     \or\psdots(0.35\wd\PBox,-0.1)(0.65\wd\PBox,-0.1)%b%b
        \psdots(-0.05,0.35\ht\PBox)(-0.05,0.65\ht\PBox)%l
        \psdots(0.35\wd\PBox,1.2\ht\PBox)(0.65\wd\PBox,1.2\ht\PBox)%t
     \fi
   \end{pspicture}}
\newlength\RCircle\newlength\PDiff\PDiff=5pt
\def\TwoDotsA#1#2{%
   \RCircle=#1
   \begin{pspicture}(-\RCircle,-\RCircle)(\RCircle,\RCircle)
     \pscircle{\RCircle}
     \psset{dotsize=2pt, linecolor=black}
     \ifcase#2
       \psdots(1.25\RCircle,0.5\PDiff)(1.25\RCircle,-0.5\PDiff)%r
     \or\psdots(-1.25\RCircle,0.5\PDiff)(-1.25\RCircle,-0.5\PDiff)%l
     \or\psdots(-0.5\PDiff,-1.25\RCircle)(0.5\PDiff,-1.25\RCircle)%b
     \or\psdots(-0.5\PDiff,1.25\RCircle)(0.5\PDiff,1.25\RCircle)%t
     \or\psdots(1.25\RCircle,0.5\PDiff)(1.25\RCircle,-0.5\PDiff)%r
        \psdots(-1.25\RCircle,0.5\PDiff)(-1.25\RCircle,-0.5\PDiff)%l
    \or\psdots(-0.5\PDiff,-1.25\RCircle)(0.5\PDiff,-1.25\RCircle)%b
        \psdots(-1.25\RCircle,0.5\PDiff)(-1.25\RCircle,-0.5\PDiff)%l
        \psdots(-0.5\PDiff,1.25\RCircle)(0.5\PDiff,1.25\RCircle)%t
     \fi
   \end{pspicture}}
\begin{document}
{\LARGE
\begin{enumerate} 

\item \TwoDots{O}{0}%r
\item \TwoDots{O}{1}%l
\item \TwoDots{O}{4}%lr
\item \TwoDots{O}{2}%b
\item \TwoDots{O}{3}%t
\item \TwoDots{O}{5}%blt
\end{enumerate}
}

\begin{enumerate} 

\item \TwoDotsA{10pt}{0}%r
\item \TwoDotsA{10pt}{1}%l
\item \TwoDotsA{10pt}{4}%lr
\item \TwoDotsA{10pt}{2}%b
\item \TwoDotsA{10pt}{3}%t
\item \TwoDotsA{10pt}{5}%blt
\end{enumerate}

\end{document}



-- 
http://TeXnik.de/
http://PSTricks.de/
ftp://ftp.dante.de/tex-archive/info/math/voss/Voss-Mathmode.pdf
http://www.dante.de/faq/de-tex-faq/
http://www.tex.ac.uk/cgi-bin/texfaq2html?introduction=yes