Transitional oscillations

Up to now the four-orbital model-based theory of porphyrin absorption electronic spectra ( ) has not taken into account the influence of NH-tautomerism in non-symmetrical porphyrins on the positions and intensities of electronic transitions in the visible region. The theoretical consideration of this problem involves solving the fundamental question of the absolute orientation of electronic transition oscillators for each tautomer. First of all. 

Calculation of transition oscillator strengths and absorption spectra... 

The covalent model of hypersensitivity was developed by Choppin and coworkers [70,74] to explain (i) the observed order of sensitivity of the parameters to the environment is 72 > 74 > 7f, >, (ii) the general trend of the hypersensitive transition oscillator strength increases with estimated covalency, (iii) the observed hypersensitivity in octahedral complexes, (iv) the simultaneous occurrence of hypersensitivity and large splittings of... 

Junction parameter within the excitonic model Excitonic perturbation matrix element Transition oscillator strength Two-photon absorption transition strength N,N-Diethyl-4-(2-nitroethenyl)phenylamine Oligomer consisting of N monomers V-shape molecule with N monomers on branches g-generation dendrimer with N monomers on branches fluorene-fluorene junction... 

Electronic States Vertical Transition Oscillator Adiabatic Product... 

These observations indicate that the photoluminescence is associated mainly with the cw-stilbene part of the silacyclobutene molecule but that the group on the silicon atom affects the characteristics of the electronic transitions (oscillator strengths, non-radiative paths) by modifying the electron density of the o-bonds at the Silicon. 

From these third and fourth terms in Eq. (6), the f-f transition oscillator strengths can finally be represented in terms of the JO type equation (Eq. 1). Only the formula of the JO intensity parameter xx is changed as follows,... 

From Tx, determined by oscillator strength measurements in absorption, it is possible to obtain the laser transition oscillator strength from table 5 and eq. (123). It has been verified that the result is nearly constant for non-centrosymmetric crystals (Auzel and Michel 1975), as shown in table 6 where the integrated cross-section has been obtained using eqs. (117) and (121). Using the average value of 3.7x 10 cm, an estimate of the laser cross-section for any Nd -doped material can be obtained as (Auzel 198T)... 

After the period of transitional oscillations an established oscillation remains. For established sinusoidal oscillations the amplitude- and phase-frequency characteristics can be obtained simply by substitution of the external frequency (o instead of the variable ca. It follows from Eq. (21) that the amplitude- and phase-frequency characteristics of the bubble or drop volume oscillations are described by Eqs. (40) and (41) where the constant Ao is either bPo/Gj or... 

Nargizyan and Rashkeev (1991) have calculated the EELS for TiN, VN, ZrN, NbN and similar carbides by the LMTO method. The transition oscillator strengths and interband DOSs have been determined. The energies of the main and additional absorption bands show a good fit to the experimental data, although some differences do exist in the fine details of the calculated and experimental spectra. 

Another advance permitted by configuration interaction is a precise calculation of other properties such as the magnetic behaviour under weak fields. The Zeeman effect in PrCb is totally reproduced by the configuration interaction parameters (Garcia and Faucher 1989). Unfortunately, the same parameters permit only partial reproduction of the electronic transition oscillator strength (Garcia and Faucher 1992). 

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