Valence bond states

TABLE 2.4. "Back of the Envelope" Estimation of the Energies of Valence-Bond States of the X- + CH3X- XCH3 +X- SN2 reaction ... 

FIGURE 2.7. (a) Three active pz orbitals that are used in the quantum treatment of the X + CH3-Y— X-CH3 + Y Sw2 reaction, (b) Valence-bond diagrams for the six possible valence-bond states for four electrons in three active orbitals, (c) Relative approximate energy levels of the valence-bond states in the gas phase (see Table 2.4 for the estimation of these energies). 

Table I Combined binding energies (kcal/mol) for H(H20)jf clusters, where N = 2, 3, and 4. The value in parentheses is computed using 2 valence bond states for HsOf".

X This has of course been put in doubt by Anderson s proposal of resonating valence bond states (see Chapter 9). 

Figure 3.39 The minimal PSB model, cis-C5/75M7)7 for the PSB photoisomerization. The vertical line indicates the carbon-carbon bond about which the excited state isomerization occurs and defines the two sides used in the definition of the valence bond states.

F. A. Matsen, Acc. Chem. Res. 11, 387 (1978). Correlation of Molecular Orbital and Valence Bond States in tt Systems. 

THE VALENCE BOND STATE CORRELATION DIAGRAM MODEL 117... 

CONSTRUCTION OF VALENCE BOND STATE CORRELATION DIAGRAMS 119... 

Valence Bond State Correlation Diagrams for Radical Exchange Reactions... 

Some Guidelines for Quantitative Applications of the Valence Bond State Correlation Diagram Model... 

VBSCD Valence bond state correlation diagram. A VB diagram that views the barrier formation as a result of avoided crossing between two state curves that are anchored in the ground and two excited states of reactants and products. The VBSCD is a paradigm for the barrier in chemical reactions (see Chapter 6). 

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