Symmetry properties of molecular

The symmetry properties of molecular orbitals of cyclohexadiene are given in the following... 

SYMMETRY PROPERTIES OF MOLECULAR ORBITALS CORRELATION DIAGRAMS... 

In the following three sections we shall discuss four applications of quantum mechanics to miscellaneous problems, selected from the very large number of applications which have been made. These are the van der Waals attraction between molecules (Sec. 47), the symmetry properties of molecular wave functions (Sec. 48), statistical quantum mechanics, including the theory of the dielectric constant of a diatomic dipole gas (Sec. 49), and the energy of activation of chemical reactions (Sec. 50). With reluctance we omit mention of many other important applications, such as to the theories of the radioactive decomposition of nuclei, the structure of metals, the diffraction of electrons by gas molecules and crystals, electrode reactions in electrolysis, and heterogeneous catalysis. 

In this section we shall discuss the symmetry properties of molecular wave functions to the extent necessary for an under-... 

FIGURE 2.3 Symmetry properties of molecular orbitals of cyclobutene and butadiene. 

Other combinations of reactants such as two k electrons with two ti electrons or four K electrons with four k electrons do not react under thermal conditions, but readily react if they are irradiated with visible or ultraviolet light. These rules of reactivity in cycloadditions were discovered by Robert B. Woodward and Roald Hoffmann on the basis of quantum-mechanical analysis and the symmetry properties of molecular orbitals. These rules are known as the Woodward-Hoffmann rules. 

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