Strength multiplet

The mechanical properties of ionomers are generally superior to those of the homopolymer or copolymer from which the ionomer has been synthesized. This is particularly so when the ion content is near to or above the critical value at which the ionic cluster phase becomes dominant over the multiplet-containing matrix phase. The greater strength and stability of such ionomers is a result of efficient ionic-type crosslinking and an enhanced entanglement strand density. 

The RQDO /-values conform with the recommended values by Wiese et al. [18] for the 3p ( P) 4s-3p ( P) 4p transitions in C//better than those of the much more complex theoretical procedure of Ojha and Hibbert [17], who used large multiconfiguration expansions in the atomic structure code CIVS. On the other hand, the discrepancies between the length and velocity CIVS oscillator strengths are not negligible. Wiese et al. [18] remark that, for the case of the 4s " P-4p multiplet, the stronger lines measured by Bengtson et al. [16] seem to be affected by self-absorption (Table 2). 

Table 5 Oscillator strengths for the multiplet transitions in halogen atoms...

The absorption spectra of some rare earths and actinides in a molten LiNOs—KN03 eutectic have been measured [590, 591]. A comparison of the oscillator strength of the 4650 A band 7Fo 5Dz) in DCIO4 and the molten nitrate eutectic shows an increase [510] of —18 times in the latter solvent. Incidentally, the 7Fo 02 transition is a hypersensitive transition [580]. Carnall et al. [591] were able to observe some transitions between the ground state multiplets viz. 7Fo - 7F, 7F - 7F and 7Fo 7F at 4610,4930 and 3910 cm-1 respectively in the nitrate eutectic. 

For a pure LS coupling scheme, both the electric and magnetic multipole transitions are diagonal with regard to S and S. The multiplet strength is also symmetric with respect to the transposition of the initial and final terms... 

The ratio of the strength of one line in the multiplet to the strength of the whole multiplet is called the relative line strength S in the multiplet... 

The quantity g(J)/g(LS) stands for the relative statistical weight of the J level in the LS term. Therefore, formulas (24.12) and (24.13) show that the sum of relative line strengths of the multiplet with given initial or final level is equal to the relative statistical weight of this level in the term. 

Line and multiplet strengths are useful theoretical characteristics of electronic transitions, because they are symmetric, additive and do not depend on the energy parameters. However, they are far from the experimentally measured quantities. In this respect it is much more convenient to utilize the concepts of oscillator strengths and transition probabilities, already directly connected with the quantities measured experimentally (e.g. line intensities). Oscillator strength fk of electric or magnetic electronic transition aJ — a J of multipolarity k is defined as follows ... 

Hence, the total probability of transitions from the level aJ to all levels within a given multiplet does not depend on J. The same is true for oscillator strengths. Therefore, if the populations N and N2 of the levels J and J2 follow the rule... 

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