Molecular orbitals atoms

Rotational and Dipole Strength Calculations for the CH-Stretching Vibrations of L-alanine Using the Localized Molecular Orbital, Nonlocalized Molecular Orbital, Atomic Polar Tensor, and Fixed Partial Charge Models ... 

Figure 1.9 shows the three-dimensional shape of the electron distributions Pmo2px and symmetry element is called a C axis. An orbital with this kind of symmetry is called a 77 orbital. Atomic orbitals of the s type can form only a molecular orbitals atomic... 

Atomic orbitals Molecular orbitals Atomic orbitals... 

To obtain qualitative information about a molecule, such as its molecular orbitals, atomic charges or vibrational normal modes. In some cases, semi-empirical methods may also be successfully used to predict energ) trends arising from alternate conformations or substituent effects in a qualitative or semi-quantitative way (but care must be taken in this area). 

In thissection we cons de [ homonuclear diatomic molecules (those composed of two identical atoms) of elements in Period 2 of the periodic table. Since the lithium atom has a 15 25 electron configuration, it would seem that we should use the Li I5 and 2s orbitals to form the molecular orbitals of the Ll2 molecule. However, the I5 orbitals on the lithium atoms are much smaller than the 2s orbitals and therefore do not overlap in space to any appreciable extent (see Fig. 9.31). Thus the two electrons in each I5 orbital can be assumed to be localized and not to participate in the bonding. To participate in molecular orbitals, atomic orbitals must overlap in space. This means that only the valence orbitals of the atoms contribute significantly to the molecular orbitals of a particular molecule. 

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