Strong resonances

Mukamel S and Shan K 1985 On the selective elimination of intramolecular vibrational redistribution using strong resonant laser fields Chem. Rhys. Lett. 5 489-94... 

Lounis B, Jelezko F and Orrit M 1997 Single molecules driven by strong resonant fields hyper-Raman and subharmonic resonances Phys. Rev. Lett. 78 3673-6... 

Total radical stabilization energy of 19.8 kcal/mol implies 10 kcal/mol of excess radical stabilization relative to the combined substituents. CH—N(CH3)2 rotational barrier is > 17 kcal/mol, implying strong resonance interaction. 

Nitro and Other Electron-Withdrawing Substituent. The presence of unsaturated groups such as nitro at conjugative positions should cause strong resonance interaction in the transition state since a nucleophilic reagent is electron-repelling (structures 48-50). At positions of the... 

Direct connection of pendant heteroatom to polystyrene aryl is a synthetically more difficult, but often still feasible (37), alternative. However, though bonds from phenyl to many common heteroatoms are relatively strong, resonance stabilization of partial positive charge developed on an arylated atom activates it to leave other substituents alkyl anilium salts (12) and anilines (38), as well as phenolic esters (39), are relatively easy to cleave. Aryl linkages,... 

When carotenoids such as lutein and zeaxanthin are excited by wavelengths in the -450-550 nm range, they exhibit particularly strong resonance Raman signals that can be used to quantify the amount of carotenoid present. The application of this technique for quantifying the macular carotenoids has been developed, thereby providing another noninvasive physical method for MP measurement. A detailed description of this method is given in Chapter 6. 

HB-2) unusually long bond lengths Rab and Rue, corresponding to high populations of <7Ab an(l obc antibonds and strong resonance mixing (3.197) ... 

Thus, neither hypervalency nor strong resonance delocalization is implied by Lewis s original electron-dot picture, which rests on a distinctly ionic (not electroneutral ) picture of the bonding. 

Finally, Table 3.42(c) summarizes the qualitative NRT results, confirming that (except for terminal obh bonds) the B—B and B—H bond orders all involve strong resonance mixing. 

As described in Section 3.5, any polar M—L bond is susceptible to backside attack by a Lewis base I. to form a linear (or near-linear) 3c/4e /ryperbonded L i- M -i L triad, equivalent to strong resonance mixing of the form... 

PC-board It was shown that a very small number of atoms can be detected by monitoring through single-mode optical fiber under strong resonant laser... 

Stabilization of the vinyl cations 8-10 by aryl substituents is important but even substituents without strong resonance effects provide adequate stabilization to allow the synthesis of persistent vinyl cations at ambient temperature. This is demonstrated by the synthesis and isolation of the salts of alkyl-substituted vinyl cations 19 and 20, and their characteristic NMR parameters are summarized in Table 1. 

As stated earlier, the benzene molecule is stabilized by strong resonance consequently, removal of a H from the ring by pyrolysis or 02 abstraction is difficult and hence slow. It is not surprising, then, that the induction period for benzene oxidation is longer than that for alkylated aromatics. The high-temperature initiation step is similar to that of all the cases described before, that is,... 

Fig. 4.46. Plot of theoretical lines of instability corresponding to the relation ji/2 3r + z/2pz = 1 for different orders N =i + rij,. Strong resonances are represented by thick lines, weak ones by dashed lines. Reproduced from Ref. [145] by permission. Elsevier Science, 1996.

Resonance Raman effects in halogen gases have been observed by Holzer etal. 207a). with an appropriate choice of exciting lines from an argon laser either resonance Raman effect or resonance fluorescence could be observed. The difference between the two spectra is discussed. In the case of a strong resonance Raman effect, overtone sequences up to the 14 harmonic could be observed. 

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