3t bands

For 3T, a broad A band was observed that becomes spectrally narrower within the first picosecond. The maximum of A1 lies at X = 600 nm. Additionally, small positive values of AD at very small delay times, indicating a further transient absorption A0, were found. The transient behavior of 4T showed that the maximum of A was found at about X = 770 nm. It was found that the whole absorption band A decays simultaneously and single exponentially with x = 530 ps. Positive AD values due to an absorption A0 seem to appear weak at zero decay. 

FIGURE 4.3 The hand structure of nickel. Note the shape of the 3t/band. 

When evaluating the energy differences, one should take the 0-phonon transitions of 1S and 3T into account and not the maximum of the band envelope. 

Finally, it is noted that the splitting of the middle band in the [Ni(H20)6]2+ spectrum arises from spin-orbit interaction between the 3T S(F) and 1Eg states (cf. Fig. 8.5.9). These two states are close in energy at the A0 value generated by six H20 molecules. But they are far apart at the stronger field of three en molecules. As a result, no splitting is observed in the spectrum of [Ni(en)3]2+. 

FIG. 6.21 Observed tc-tc band maximunri and absorbance at the maximum for the 7C-tc band of aggregated (323 nm) and nonaggregated (348 nm) trans-chromophores, as well as the absorbance at the n-3T band (characteristic for the cis-isomer) as a function of the irradiation time (at X == 360 nm) of a LBK film of polymer 38 (reproduced with permission from reference 93). 

In the low energy region the measurements of Alien et al. went down only to 4 kK. but hexachlorobutadiene mull data indicated the presence of a further band at 3.0—3.4 kK.. This and the 5.6 kK. band were therefore readily identified as transitions within the spin-orbit split ground state manifold — the 3 kK. absorption as 3Tig (A) - 3i g (A) and the 5.6 kK. peak as 3Tlg (A) -+3T g (A, A). Allen et al. were unable to resolve the broad band at 30 kK. but it may be noted that six formally 

The other doubledeckers containing the metals La, Pr, Nd, Sm -Lu have rather similar spectra that have less well distinct bands in the visible region. The extinction at 573 nm is much less than in A, Peaks occur at about 540 and 670 nm. The latter absorption is typical for 3T-cation radicals (10), Indeed, the composition Ln(0EP)2 can only be accomodated with the normal trivalent state of nearly all of the lanthanoid ions if one assumes that the 

For ruthenium and the following elements of the 4d series the free-ion f values become in excess of 1000 cm-1, and apart from the exceptions mentioned previously, the relative intensities of the spin-forbidden bands are found to be significantly larger than for the 3d elements. For the intra-subshell (t g) transitions 3T g XT%g and 3T g 1Eg some 2% 

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