Vibrations sodalite

K. A. Iyer and S. J. Singer, /. Phys. Chem., 98, 12670 (1994). Local Mode Analysis of Complex Zeolite Vibrations Sodalite. 

Between 3500 and 3600 cm"1 we can observe vibrations due to the OH groups pointing inside the sodalite cavities, i.e. the low frequency band at 3570 cm"1 and the associated band perturbed by the extra framework phase at 3525 cm"1. 

The table 1 shows that the asymmetric stretching vibration, va linearly decreases with increasing amount of silver exchanged. This shift in IR frequency as a function of silver exchange is explained on the basis of cell constant. The silver halide sodalites have a... 

Time-resolved luminescence spectroscopy of sodalite evidences that the vibration structure has a very short decay time and disappears after a delay of 250 ns. Such structure is superimposed on the very broad IR band (Fig. 4.65). 

Cation Siting in Linde A. At the time this work was completed, x-ray studies on hydrated NaA (3, 4) and hydrated KA (5) had shown that 8 of the 12 exchangeable cations per unit cell are firmly bound to the zeolite framework and would therefore be expected to have the major influence on the lattice vibrations. These cations are sited in front of the sodalite... 

Cis structure, where CO groups occupy one axial and one equatorial position, would present two bands this configuration is the only one which agrees with all experimental observations. The two CO s are free to vibrate in the sodalite cage and point towards the hexagonal windows of the supercages. 

Class B Quantum Supralattices. An interesting series of sodalite materials that for the first time offer the opportunity to manipulate the degree of collective electronic and vibrational interactions between monodispersed semiconductor components in neighboring /3-cavities (Figure 1) can be synthesized as follows ... 

An elegant way to get 0-H vibrational frequencies from short ab initio MD trajectories is based on the monitoring ofroH(t), obtaining the instantaneous vibrational frequencies from the time delay, r, between two consecutive maxima as w = 27r/r. A vibrational density of states can be constmcted from the histogram of the instantaneous frequencies, giving some pieces of information about the expected width of the corresponding IR band. The OH frequency, about 3550 cm , obtained by this procedure from Car-Parrinello PAW trajectories for the sodalite framework is very close to the experimentally expected value. 

Inelastic and quasielastic neutron scattering have special advantages for studying certain of the motional properties of protonated or organic species within zeolites and related microporous materials. These advantages and various experimental methods are outlined, and illustrated by measurements of torsional vibrations and rotational diffusion of tetramethylammonium (TMA) cations occluded within zeolites TMA-sodalite, omega, ZK-4 and S APO-20. 

K. S. Smirnov and D. Bougeard,/. Phys. Chem., 97, 9434 (1993). Molecular Dynamics Study of the Vibrational Spectra of Siliceous Zeolites Built from Sodalite Cages. 

The results are in contrast to what is obtained for the dealuminated Y, HYD, which has also strong acid sites (7). Figure 3 shows that pyridinium ions are not detected for an evacuation temperature of 675 K or higher. The hydroxyls in the sodalite cage vibrating at 3555 cm-i already reach their full... 

Nevins N, K Chen and N L Allinger 1996c Molecular Mechamcs (MM4) Vibrational Frequency Calculations for Alkenes and Conjugated Hydrocarbons. Journal of Computational Chemistry 17 730-746 Nicholas J B, A J Hopfmger, F R Trouw and L E Iton 1991 Molecular Modelling of Zeolite Structure. 2. Structure and Dynamics of Silica Sodalite and Silicate Force Field. The Journal of the American Chemical Society 113.4792-4800. 

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