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Symmetry orthogonality

Orthogonalize (using Eowdin (symmetrie) orthogonalization) the following Is (eore), 2s (valenee), and 3s (Rydberg) STO s for the Ei atom given ... [Pg.200]

SINDOl is a semiempirical method based on the INDO model and derives its name from an approximate transformation to symmetrieally orthogonalized orbitals. Since the new version of this method, MSINDO (see Section 2.38.3.6), is more accurate, should be used instead of SINDOl. [Pg.477]

Finally, two other structural types of metallocenes need to be mentioned. One type consists of carbocyclic itt-ligands, which are not identical but each possessing a plane of symmetry (orthogonal to the ring plane). These t3T>es of metallocenes are labeled as Cs-S5unmetric. The other type of metallocene contains two nonidentical carbocyclic ligands, one sjunmetrical and one asymmetrical. These types of... [Pg.6796]

An orientational order parameter can be defined in tenns of an ensemble average of a suitable orthogonal polynomial. In liquid crystal phases with a mirror plane of symmetry nonnal to the director, orientational ordering is specified. [Pg.2555]

Using the orthogonality of eharaeters taken as veetors we ean reduee the above set of eharaeters to Ai + E. Henee, we say that our orbital set of three Ish orbitals forms a redueible representation eonsisting of the sum of and E IR s. This means that the three 1 sh orbitals ean be eombined to yield one orbital of Ai symmetry and a pair that transform aeeording to the E representation. [Pg.592]

If there are two orthogonal planes of material property symmetry for a material, symmetry will exist relative to a third mutually orthogonal plane. The stress-strain relations in coordinates aligned with principal material directions are... [Pg.59]

Principal material directions (PMO) are directions that are parallel to the Intersections of the three orthogonal planes of material property symmetry. Principal material coordinates (PMC) are the set of axes In principal material directions. [Pg.59]

The carbides of the lanthanoids and actinoids can be prepared by heating M2O3 with C in an electric furnace or by arc-melting compressed pellets of the elements in an inert atmosphere. They contain the C2 unit and have a stoichiometry MC2 or M4(C2)3. MC2 have the CaC2 structure or a related one of lower symmetry in which the C2 units lie at right-angles to the c-axis of an orthogonal NaCl-type cell. They are more reactive than the alkaline-earth metal... [Pg.298]

The structure of cyclo-Sio is shown in Fig. 15.5(b).The molecule belongs to the very rare point group symmetry Do (three orthogonal twofold axes of rotation as the only symmetry elements). ITie mean interatomic distance and bond angle are close to those in cyclo-Su (Table 15.5) and the molecule can be regarded as composed of two identical S5 units obtained from the S 2 molecule (Fig. 15.6). [Pg.657]

Finally, DFT methods are at present not well suited for excited states of the same symmetry as the ground state. The absence of a wave function makes it difficult to ensure orthogonality between the ground and excited states. [Pg.189]

Figure 6-3. Top Structure of the T6 single crystal unit cell. The a, b, and c crystallographic axes are indicated. Molecule 1 is arbitrarily chosen, whilst the numbering of the other molecules follows the application of the factor group symmetry operations as discussed in the text. Bottom direction cosines between the molecular axes L, M, N and the orthogonal crystal coordinate system a, b, c. The a axis is orthogonal to the b monoclinic axis. Figure 6-3. Top Structure of the T6 single crystal unit cell. The a, b, and c crystallographic axes are indicated. Molecule 1 is arbitrarily chosen, whilst the numbering of the other molecules follows the application of the factor group symmetry operations as discussed in the text. Bottom direction cosines between the molecular axes L, M, N and the orthogonal crystal coordinate system a, b, c. The a axis is orthogonal to the b monoclinic axis.
Although it would be possible in principle to choose any set of orthogonal axes in the structural unit to define Ox,x2x3, it is implicit in the discussion of orientation in polymers that the structural unit also has at least orthorhombic symmetry (Point group D2) with regard to the development of orientation. As can be appreciated this can lead to an element of awkwardness in dealing with the results of orientation measurements, because the molecular situation is often more complicated. [Pg.84]

The K conjugate molecules usually have planar geometries and no difference between the two faces above and below the molecular plane. When substitutions break the symmetry with respect to the plane, n orbitals mix a orbitals orthogonal prior to the substitution. Rehybridization occurs and the unsaturated bonds have... [Pg.60]


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See also in sourсe #XX -- [ Pg.79 ]




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