Application to linear polyenes

W. Wu, S. J. Zhong, S. Shaik, Chem. Phys. Lett. 292, 7 (1998). VBDFT(s) A Hiickel-Type Semi-empirical Valence Bond Method Scaled to Density Functional Energies. Application to Linear Polyenes. 

W. Wu, Y. Luo, L. Song, S. Shaik, Phys. Chem. Chem. Phys. 3, 5459 (2001). VBDFT(s) A Semiempirical Valence Bond Method Application to Linear Polyenes Containing Oxygen and Nitrogen Heteroatoms. 

Type Semi-empirical Valence Bond Method Scaled to Density Functional Energies. Applications to Linear Polyene. 

A Semiempirical Valence Bond Method Application to Linear Polyenes Containing Oxygen and Nitrogen Heteroatoms. 

Wei W, Zhong SJ, Shark S (1998) VBDFT(s) a Huckel-type semi-empirical valence bond method scaled to density functional energies. Application to linear polyenes. Chem Phys Lett 292 7-14... 

Wu W et al (2001) VBDFT(s) - a semi-empirical valence bond method application to linear polyenes containing oxygen and nitrogen heteroatoms. Phys Chem Chem Phys 3 5459-5465... 

Application of the circle method to linear polyenes. (Adapted from reference 2e.)... 

V-UV Application First Excited State of Linear Polyenes. The first electronic absorption band of perfect linear aromatic polyenes (CH)X, or perfect polyacetylene shifts to the red (to lower energies) as the molecule becomes longer, and the bond length alternation (BLA) would be zero. This was discussed as the free-electron molecular orbital theory (FEMO) in Section 3.3. If this particle-in-a-box analysis were correct, then as x > oo, the energy-level difference between ground and first excited state would go to zero. This does not happen, however first, because BLA V 0, next, because these linear polyenes do not remain linear, but are distorted from planarity and linearity for x > 6. 

In this section the simplicity of freeon dynamics is illustrated by its application to polyenes [6]. Here I relate molecular-orbital Gel fand states to atomic-orbital Gel fand states and then relate the atomic-orbital Gel fand states to valence bond states. Note that this construction provides a theoretical basis for the Rumer rule i.e., for the number of linearly independent valence bond states. We then use this freeon dynamics to explicate the spin paradigm. 

For any application of the Cioslowski formula we must know at least something about the function F(x). In [110] it was established that F(l) = 1. In [106] trial-and-error attempts were made to guess the (approximate) form of F(x), but the results obtained were not conclusive. Quite recently Cioslowski proposed [111] what he calk a final solution of the problem" by adjusting F(x) to the eigenvalue distribution of annulenes (Ft) and linear polyenes (F2). He deduced [111]... 

The adiabatic approximation is widely accepted as being applicable to the electronic states of conjugated polymers. As described above, solutions of an adiabatic Hamiltonian (namely, the Pariser-Parr-Pople-Peierls model) agree remarkably well with experimental observations for short polyenes. A linear extrapolation in inverse chain length of the experimental observations coincide with the experimental observations of the energies of the and states in thin... 

In this review, we discuss the electrode/electrochemical properties and technological applications of -conjugated polymers. It is organized by material and the matmals are grouped in two classes, the polyaromatic polymer films such as the polymer derivatives of aniline, pyrrole, and thiophene, and the linear polyenes such as polyacetylene, polythiazyl. The report does not intend to review the preparation procedures or the physical properties of these materials since they have been summarized elsewhere It is also limited to work published in the scientific literature without attempting to include the numerous patents which have appeared in the last few years. 

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