On the basis of the parameters identified in the first paper of this series of two, the spectral distribution curves of the absorption coefficient in the IR spectral interval for a silsesquioxane organometallic complex were calculated. Good agreement with experimental data was obtained. A detailed interpretation of the spectra was made, and it was shown that the most of the bands in the spectra are the result of superposition of a large number of vibrations. Conclusions about the structure of the investigated molecules were made.

On the basis of the IR spectroscopy method and by detailed calculation of the spectral curves with regard to the distribution of the absorption band intensities, the structure of the silsesquioxane organometallic complex was investigated. Part one is devoted to the discussion of the calculation method. It is shown that the calculations have to be semi-empirical and modeling. All parameters (geometrical parameters, force constants, electro-optical parameters) required for the construction of molecular models are identified and described in detail. The complication of the spectra interpretation associated with superposition of a large number of absorption bands in the examined molecules is noted.

Theoretical vibrational spectra of the leucoemeraldine form of neutral reduced polyaniline are presented, based on a single-periodic-chain model and a harmonic potential with parameters transferred from the molecules dyphenylamine and N,N'-diphenyl-p-phenylenediamine. The out-of-plane degrees of freedom and the infrared-absorption intensities are included in the calculations. Several experimental spectra are analyzed and compared with the theoretical ones. Our comparative analysis enables conclusions concerning packing density, spatial and electronic structure, and electron-phonon coupling of the samples of different origin.

Vibrational frequencies of an α para-dichlorobenzene crystal are calculated. By solving an inverse spectral problem, the series of force constants of an isolated p-C6H4Cl2 molecule were found. It was shown that this series can be carried over to the crystal model. This means that during crystallization, the electronic structure of a p-C6H4Cl2 molecule stays constant. Intermolecular interaction was modeled upon pseudo-bonds. Force constants were estimated from the calculation of intermolecular interaction energy, by the way of a Monte-Carlo simulation. Vibrational dynamics of the crystal and isolate molecule were analyzed. Absorption bands sensitive to the crystallization of the molecule were found.

Theoretical infrared (ir) spectra of trans- and cis- forms of poly(p-phenylene vinylene) (PPV) are presented, based on a single-periodic-chain model and harmonic potential with parameters transferred from p-divinyl benzen molecule. The out-of-plane degrees of freedom and the infrared intensities were included in the calculations.The calculations of polarized infrared spectra of cis- and trans-PPV do not show practically any difference. However, as the calculations evince the absence of the in-plane C-H bending infrared absorption band of trans-vinylene portion of experimental infrared spectrum of PPV, which is a consequence of a delocalized pi-electron system (similarly to the case of trans-polyacetylene but not cis-polyacetylene), it seems that stereochemical structure of PPV is of the trans-form. Additional X-ray analysis is still necessary to support our conclusion.

Theoretical vibrational spectra of trans-polyacetylene (PA), poly(p-phenylene) (PPP) and poly(p-phenylene vinylene) (PPV) are presented, based on a single-periodic-chain model and a harmonic potential with parameters transferred from trans-hexatriene, toluene, and p-divinyl benzene, respectively. The out-of-plane degrees of freedom and the infrared absorption intensities were included in the calculations.The calculations evince the absence of the in-plane C-H bending infrared absorption band of the trans-vinylene portion of trans-PA and PPV, which is a consequence of a delocalized pi-electron system. The electron-phonon coupling in PPP and PPV is relatively weak - in contrast to trans-PA, where the frequencies of the principal Raman lines are significantly lowered. As a consequence, the PPV is an example of pristine polymer with well delocalized pi-electron system, but without significant electron-phonon coupling.

Theoretical vibrational spectra of poly(p-phenylene vinylene) (PPV) are presented, based on a single--periodic-chain model and a harmonic potential with parameters transferred from n-divinyl benzene. The out-of-plane degrees of freedom and the infrared-absorption intensities were included in the calculations. The calculations evince a missing of the in-plane C-H bending infrared-absorption band of the trans-vinylene portion of PPV, as in trans-polyacetylene, which is a consequence of delocalized \ensuremath{\pi}-electron system. However, the electron-phonon coupling in PPV is relatively weak [as in poly(p-phenylene)] as compared to trans-polyacetylene (where the frequencies of the principal Raman lines are significantly lowered). As a conequence, PPV is an example of pristine polymer with well-delocalized \ensuremath{\pi}-electron system, but without significant electron-phonon coupling.

Spectral distribution curves of the absorption coefficients of vibrational spectra of two poly(phenylene vinylene) conformations are calculated. Vibration dynamics are analyzed and absorption bands sensitive to the polymerization are revealed. Histograms of electronic states for isolated polymeric chains are calculated with the help of the Hückel extended method. The values of force constants and of electro-optical parameters found previously are shown to be convenient for reasonably accurate description of the IR spectra of the polymer; these show that at polymerization the electronic structure of isolated structural elements stays constant. A feeble influence of the intermolecular interactions on the spectra of basic chains is discovered, that makes it possible to use an approximation to examine these chains independently of their environment. The histograms of the electronic states show that these polymers can have semiconductor features.