From rpm@wag.caltech.edu  Fri Sep 18 01:20:47 1992
Date: Fri, 18 Sep 1992 08:20:47 -0700
From: "Richard P. Muller" <rpm@wag.caltech.edu>
To: chemistry@ccl.net
Subject: Mathematica modules for Brackets



Has anyone written any Mathematica (or Maple, or CALC, or whatever)
rules for the simplification of "brackets" matrix elements such as are
found in quantum chemical energy expressions? I just started writing
some, and I would be interested in what others have done along these
lines. 

For example, if the energy of two electrons in orbital a is
E = 2 <a|h|a> + (aa,aa)
and we vary a to be a+x*b, how does the energy change?
E' = 2<a|h|a> + 4x*<a|h|b> + (aa,aa) + 4x*(aa,ab) + ...

It isn't difficult to work these expressions out, just tedious, and
I'm worried that I'll make some careless errors which will later be
incorporated into my programs. It should be easy to write some simple
rules for Mathematica to follow. If anyone has already done something
like this let me know; I will post whatever rules I finally come up
with to the mlist.

Thanks in advance for your time.
     	  	    	      			 -Rick Muller
     	  	    	      			  rpm@wag.caltech.edu