Linear spectroscopic studies

Next, we discuss the concept of phonon-assisted reactions. In relation to thermal reactions, they can be assisted by phonon-mode softening leading to large-amplitude overdamped oscillations. In the case of a photochemical reaction, a strong electron-phonon coupling can assist in polymerization. Then some non-linear spectroscopic studies are discussed which illuminate on the dynamics of photopolymerization process. Then follows a discussion of results on reaction in a different kind of molecular assembly, the Langmuir-Blodgett films. Finally, some gas-solid interface reactions which produce polymers in a doped state are discussed. 

Other Linear Spectroscopic Studies at the Neat Liquid/Liquid Interface... 

Early experimental spectroscopic investigations on Rg- XY complexes resulted in contradictory information regarding the interactions within them and their preferred geometries. Rovibronic absorption and LIF spectra revealed T-shaped excited- and ground-state configurations, wherein the Rg atom is confined to a plane perpendicular to the X—Y bond [10, 19, 28-30]. While these results were supported by the prediction of T-shaped structures based on pairwise additive Lennard-Jones or Morse atom-atom potentials, they seemed to be at odds with results from microwave spectroscopy experiments that were consistent with linear ground-state geometries [31, 32]. Some attempts were made to justify the contradictory results of the microwave and optical spectroscopic studies, and... 

Rimai, L., Heyde, M.E., and Gill, D. 1973. Vibrational spectra of some carotenoids and related linear polyenes. A Raman spectroscopic study. J. Am. Chem. Soc. 95 4493 4501. 

N-Cyanourea Oligomers as Coating Materials. Previously, the difunctional N-cyanourea-terminated oligomers were used to prepare thermoset plastics at a temperature higher than 100°C.Q) It was reported that the oligomers, upon heating, underwent the same major polymerization as equations (5) and (6) in linear polymer preparation. Some side reactions, based on IR, NMR and mass spectroscopic studies were proposed to illustrate the formation of cross-links, as shown in Figure 4. 

Cadmium complexes have not been neglected in these and other physical studies. For example, an electron diffraction study of CdBr2 has been made, and it was concluded that the equilibrium structure corresponds to a linear Br—Cd—Br molecule, with a Cd—Br distance of 2.372 A and a Br—Br distance of 4.694 A.105 Raman and IR spectroscopic studies of CdCl2 have also been reported.106 The Cd2+—en system is of interest, and a detailed study of the vibrational spectra (IR and Raman) of [Cd(en)(N02)2] and its deuterated derivative has been reported.107... 

N(I) Compounds. Hydration of nrtrogen(I) oxide, NjO to hyponitrous arid, H2N2O2, is not possible. However, the latter decomposes (in three steps) to yield the former, which is thus its anhydride. Spectroscopic studies indicate a linear structure for N50, resonating between... 

For earlier results from matrix spectroscopic studies which assigned a linear SiSiO structure to the triplet state of this molecule, see R. J. VanZee, R. F. Ferrante and W. Weltner, Chem. Phys. Lett., 139, 426 (1987). 

Another approach used in the empirical characterization of liquid polarity is the study of the outcome of a chemical reaction. Earle et al. [216] report a preliminary study of the keto-enol tautomerization of pentane-2,4-dione, and create an empirical correlation between the degree of tautomerization and the dielectric constant of molecular liquids. They then predict dielectric constants for a series of ILs based on the observed keto-enol equilibrium the values range from 40 to 50, slightly higher than those of short-chain alcohols. A more detailed study by Angelini et al. [217] considers the tautomerization of a nitroketone complex in a series of five imidazolium-based ILs. The results, parameterized as a linear free energy analysis of the behavior of the equilibrium constant, indicates an overall polarity comparable to that of acetonitrile, consistent with the partitioning and spectroscopic studies referenced above. 

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