Quadrupolar pattern

Comparison of the energies for TPA and OPA shows a higher energy for the TP excited state compared to the lowest allowed OP excited state (Si) for all chromophores (99-107) examined in this section. Hence, the amplitude of TPA can be described by Eq. (27). There are no dipolar contributions, no matter that solvatochromism occurs for the samples 99-104. The influence of the quadrupolar pattern is reflected in M12. Application of models of the symmetry break are not likely to provide clarification of the relation between TPA properties and the distinct quadrupolar substitution of the chromophores 99-107. 

D-7i-A)3-D chromophores exhibit large TPA, as shown for chromophore 122 [490]. This compound can be considered a propeller-shaped molecule consisting of three quadrupolar arms. This study demonstrates that addition of each individual arm results in a twofold increase of 8 as shown for the TPA of 122 (5 = 5030 GM) in comparison with the quadrupolar chromophore 100c (7) = 1370 GM). The latter comprises one arm of 122. Substitution of one arm by a methyl group results in a twin chromophore exhibiting a 8 of 3130 GM. Thus, one can conclude that TPA depends on the number of arms (na), na > 2, incorporated in both (D-rc- A)na-D and (D-7i)na-D chromophores. The structural pattern of 122 comprises three quadrupolar arms. Thus, Eqs. (59) and (60) cannot be applied to describe TPA of 122 because A/(m 0 due to the quadrupolar pattern of each arm. Therefore, the enhacement of 8 is better explained by the increase of the transition dipole moments Mqi and M 2 because... 

Figure 8 gives tlie pattern obtained for an aqueous suspension of 80 nm gold metallic particles. The pattern no longer follows the form of expression Eq. (15) and now resembles more closely that of a quadrupolar pattern with four lobes. In fact, for 80 nm diameter particles, retardation effects must be taken into account. The total scattered field at the harmonic frequency cannot be described with the pure local contribution only. One has to introduce the non local contribution too. The polarization pattern of the HRS intensity takes the following general form [44] ... 

The collapse of a six-line hyperfine spectrum with decreasing relaxation time is illustrated by the calculated spectra in Fig. 3.8 [44] for a " Fe nucleus in a fluctuating magnetic field and a fixed electric field gradient for different values of the electronic relaxation time. If the fluctuation rate is very slow compared to the precession frequency of the nucleus in the field H, the full six-line hyperfine pattern is observed. If the fluctuation rate is extremely rapid the nucleus will see only the time-averaged field which is zero and a symmetric quadrupolar pattern will be seen. At intermediate frequencies the spectra reflect the fact that the 2> -> transitions which make up the low-velocity component of the quadrupole doublet relax at higher frequencies than do the I I i> and -]-> -> transitions which... 

The state of boron in boron-modified mordenite has been investigated by "B MAS NMR and quanmm chemical calculation [04C3]. The B MAS NMR spectra consisted of a typical second-order quadrupolar pattern... 

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