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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). |