Re: tree names in group spec.

From: Bill Ross <>
Date: Thu 10 May 2001 18:37:01 -0700 (PDT)

        I am curious what tree names S, B, 3, E stand for in Group

These are topological types. From the prep doc:

           Any atom that is not a main atom is described by one of
      the other topological types: "E", "S", "B", "3", "4", "5", or
      "6". An "E" atom has only one connection to other atoms, thus
      is a "dead end" for any branch from any other atom type. An
      "S" atom must have a total of two connections to other atoms,
      a "B" atom must have a total of three connections, and a "3"
      atom actually has a total of four connections; the same applies
      for "4" "5" and "6".

Bill Ross
Received on Thu May 10 2001 - 18:37:01 PDT
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