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332. CART: Molecular Geometry Generator
by Chin-Yah Yeh, Department of Chemistry, Soochow
University, Shihlin, Taipei, Republic of China
Besides the ordinary way of generating molecular
geometry (using the geometrical parameter set including
a bond length, a bond angle, and a dihedral angle), the
program CART provides the following options to
ameliorate some of the difficult situations encountered
in constructing molecular structures:
1. When an atom is to bridge in order to close the
ring of a ring structure, CART can choose to keep the
bridging atom in proper interatomic distances with
both neighboring atoms. This option is essentially
made for the case of cyclic compounds. However, any
atom being defined by two distances and one angle can
call upon this option to obtain its coordinates.
2. When interatomic distances are readily available,
such as from crystallographic data, CART can
calculate the coordinates of an atom from the
distances to atoms of known positions. Three
distances are needed.
3. When data of bond angles are more reliable than
those of dihedral angles, CART can accept one bond
length and two bond angles to define an atom.
4. If a portion of the considered molecule has known
coordinates, that portion can be patched onto the
framework. (A framework must consist of at least
three atoms so as to define a coordinate system.)
5. CART can generate an atom which lies on the middle
point between two atoms or the equipoint of a given
atom with respect to a twofold rotation along one of
the three coordinate axes.
Input stream information is given in the COMMENT cards.
FORTRAN 63 (CDC 3000 Series)
Lines of Code: 134
Recommended Citation: C.-Y. Yeh, QCPE 11, 332 (1977).
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