Molecular orbitals of diatomic molecules

The overlap between atomic orbitals on the same center is zero our atomic orbitals are orthonormal. It is the s—p overlap on nonadjacent centers that leads 

However,. + is positive, whereas that for 4 +, + is negative because of the 

6 MOLECULAR ORBITALS OF DIATOMIC MOLECULES AND ELECTRONEGATIVITY PERTURBATION 

Orbitals of an A2 diatomic correct to the first order in energy. 

Just how much antibonding character there is in I cr+ or bonding in 2 t+ depends on the amount of s-p mixing. Likewise, whether the 2 r+ level lies below or above the 

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The system of energy levels for the molecular orbitals of diatomic molecules is often represented schematically as in Fig. 23.23, in which the energy levels of the two separated... 

Molecular Orbitals of Diatomic Molecules and Electronegativity Perturbation... 

In order to examine the workings of electronegativity perturbation, we will need to examine the orbitals of a molecule where the atoms arc not all identical and where each atom carries more than one atomic orbital. An important feature which results is that of orbital hybridization, namely the mixing of different atomic orbitals on the siinie center. In this chapter we will examine the nature of such hybridization, construct the molecular orbitals of diatomic molecules from different viewpoints, and describe the essence of electronegativity perturbations. 

Estimate the energies of the bonding and antibonding molecular orbitals of diatomic molecules from the secular determinant Construct simple molecular orbitals for diatomic molecules from a linear combination of atomic orbitals and describe their symmetry... 

Figure 3.6 shows the LCAO method for generating molecular orbitals of diatomic molecules such as H2. In real molecules, the atomic orbitals of elemental carbon are not really transformed into the molecular orbitals found in methane (CH4). Figure 3.6 represents a mathematical model that mixes atomic orbitals to predict molecular orbitals. Molecular orbitals exist in real molecules and the LCAO model attempts to use known atomic orbitals for atoms to predict the orbitals in the molecule. Molecular orbitals and atomic orbitals are very different in shape and energy, so it is not surprising that the model used for diatomic hydrogen fails for molecules containing other than s-orbitals. 

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