The B3LYP/LANL2DZ optimized geometry for Rh 13 with M = 2 is shown in
Fig. 3b. We notice that the initial geometry is not retained. The positions of the
atoms 9 and 10 are considerably modified. The plane containing the atoms 3, 4, 7,
8, 11, 12 is slightly modified in the optimization process. The calculations made for
the other multiplicities converge to a geometry similar to that found for M = 2,
which is basically maintained until the cluster with M = 26. The conformation of
minimum energy for this series corresponds to a multiplicity equal to 22, and is
presented in Fig. 3c, where we can see that the plane of the six atoms has been
distorted. Table 3 shows the energy calculated for these clusters as well as the
eigenvalues of the S
2 operator. Note that the spin contamination for these calculations is large. As expected, during the optimization process the initial geometry of
the cluster is not equal to the final geometry, i.e., during the optimization process
the geometry evolves. Geometries known as non-icosahedral or low symmetry have
Fig. 2 Isomers of Rh 8 geometry in its minimum energy conformation obtained with the ROHF/
LANL2DZ. a bi-capped octahedron, b bi-capped triangular prism, c incomplete icosahedron,
d cube
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M. A. Mora and M. A. Mora-Ramírez
Fig. 3b. We notice that the initial geometry is not retained. The positions of the
atoms 9 and 10 are considerably modified. The plane containing the atoms 3, 4, 7,
8, 11, 12 is slightly modified in the optimization process. The calculations made for
the other multiplicities converge to a geometry similar to that found for M = 2,
which is basically maintained until the cluster with M = 26. The conformation of
minimum energy for this series corresponds to a multiplicity equal to 22, and is
presented in Fig. 3c, where we can see that the plane of the six atoms has been
distorted. Table 3 shows the energy calculated for these clusters as well as the
eigenvalues of the S
2 operator. Note that the spin contamination for these calculations is large. As expected, during the optimization process the initial geometry of
the cluster is not equal to the final geometry, i.e., during the optimization process
the geometry evolves. Geometries known as non-icosahedral or low symmetry have
Fig. 2 Isomers of Rh 8 geometry in its minimum energy conformation obtained with the ROHF/
LANL2DZ. a bi-capped octahedron, b bi-capped triangular prism, c incomplete icosahedron,
d cube
218
M. A. Mora and M. A. Mora-Ramírez