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Sandorfy models

T. Di Paolo, C. Bourderon, and C. Sandorfy, Model calculations on the influence of mechanical and electrical anharmonicity on infrared intensities Relation to hydrogen bonding. Can. [Pg.46]

A red shift in the absorption maxima and a gradual increase in the molar absorption coefficients (e) can be observed with increasing chain length. This is due to the a-conjugation along the silicon main chain depending on substituent and conformational effects that can be explained by molecular orbital theory (MO). The LCAO, Sandorfy model C and FE (free electron) methods have been used. [Pg.21]

These methods appear rather simple, yet they were the starting point of a long evolution. Gilles Klopman, whose research interests at Case-Western Reserve University later turned to modeling bioactive molecules, was the first to use Sandorfy s methods. Kenichi Fukui made extensive use of them in his well-known work on the structures and reactions of saturated hydrocarbons and their derivatives. Fukui added his frontier orbital considerations. Around 1959 the milieu of developments in quantum chemistry contributed to inspire William N. Lipscomb to conceive the extended Hiickel method, which was subsequently implemented by Lawrence L. Lohr and Roald Hoffmann.83 Soon thereafter, John Pople and his coworkers introduced self-consistent field methods based on the zero-differential overlap approximation.815... [Pg.217]

There are several other results that also support the proton-transfer mechanism. The absorption spectrum of bathorhodopsin is red shifted with respect to the spectrum of rhodopsin itself, therefore, bathorhodopsin may be a more tightly protonated Schiff base than rhodopsin. Model studies by Sandorfy " show explicitly that translocating the proton toward the Schiff base nitrogen could account for the spectral red shift. [Pg.638]

Figure 11.6. Molecular orbital representations of the HOMO and LUMO of a linear polysilane based on the Sandorfy C model. Figure 11.6. Molecular orbital representations of the HOMO and LUMO of a linear polysilane based on the Sandorfy C model.
In the Sandorfy C model, the degree of delocalization can be appreciated by consideration of the ratio of the resonance integrals p for geminal (same atom)... [Pg.186]

When the parent neutral molecule has well-conjugated electronic orbitals without any interactions with orbitals in other symmetries, we note that the observed absorption transition for the radical cation and anion should be identical. This nature is widely known as the Pairing Theorem ". Concerning the (T-conjugation of the polysilane main chain, this theorem should be closely related to the Sandorfy C and H orbital models la, 15,19). In the case that this theorem is approximately valid, the electronic property of the main chain can be explained by the model C, which is a more simple approximation than the other. [Pg.331]


See other pages where Sandorfy models is mentioned: [Pg.214]    [Pg.214]    [Pg.589]    [Pg.100]    [Pg.1314]    [Pg.142]    [Pg.214]    [Pg.215]    [Pg.97]    [Pg.530]    [Pg.97]    [Pg.1219]    [Pg.4]    [Pg.384]    [Pg.148]    [Pg.149]    [Pg.186]    [Pg.1314]    [Pg.197]    [Pg.88]   
See also in sourсe #XX -- [ Pg.214 ]




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Sandorfy C model

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