Visible configuration

The phenotype (visible configuration) of the marsh plant Sagittaria sagittifolia depends on its environment. As shown in Figure 5.3.7, its leaf forms depend upon the degree to which it is submerged. Nowhere is there a better illustration of the interaction of environment with genetic expression than this. 

Since the visible configuration does not necessarily correspond to the logical one, which depends on the criterion for system failure, the addition in the sense of reliability made previously is always required for unambiguity. ... 

Yon can use a sin gle poin t calculation that determines energies for ground and excited states, using configuration interaction, to predict frequencies and intensities of an electron ic ultraviolet-visible spectrum. 

UV/Vis Spectra for Molecules and Ions When a molecule or ion absorbs ultraviolet or visible radiation it undergoes a change in its valence electron configuration. The valence electrons in organic molecules, and inorganic anions such as oc-... 

Absorption and Fluorescence Spectra. The absorption spectra of actinide and lanthanide ions in aqueous solution and in crystalline form contain narrow bands in the visible, near-ultraviolet, and near-infrared regions of the spectmm (13,14,17,24). Much evidence indicates that these bands arise from electronic transitions within the and bf shells in which the Af and hf configurations are preserved in the upper and lower states for a particular ion. 

Cerous salts in general are colorless because Ce " has no absorption bands in the visible. Trivalent cerium, however, is one of the few lanthanide ions in which parity-allowed transitions between 4f and Sd configurations can take place and as a result Ce(III) compounds absorb in the ultraviolet region just outside the visible. 

The final recommended configuration for improving dust capture is shown in Fig. 10.46. The design change was rather simple and the model test showed a significant reduction in visible fugitive emissions. 

It is possible to observe spin-allowed, d d bands in the visible region of the. spectra of low-spin cobalt(lll) complexes because of the small value of 0Dq, (A), which is required to induce spin-pairing in the cobalt(lll) ion. This means that the low-spin configuration occurs in complexes with ligands which do not cause the low -energy charge transfer bands whieh so often dominate the spectra of low-spin complexes. 

Diverse series of diphenyl sulphoxide (DPSO) complexes of Mn(II), Fe(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Ca(II), Al(II) and Mg(II) with various large anions have been reported187-191. The complexes have the general formula M(DPSO)6(Anion) where M is the metal cation. The reflection spectra in the visible and near-IR region indicate an octahedral configuration around the metal ion surrounded by the DPSO molecules. Comparison with the spectra of DMSO complexes shows that they have almost identical structures. IR spectra indicate that the oxygen atom in the sulphinyl group is the donor atom in all these complexes. 

In Zn24, the 3c/-orbitals are filled (du>). Therefore, there can be no electronic transitions between the t and e levels hence, no visible light is absorbed and the aqueous ion is colorless. The dH) configuration has no unpaired electrons, so Zn compounds would be diamagnetic, not paramagnetic. 

Another example is provided by [30] anmlene. Longuet-Higgins and Salem have shown that the observed visible and UV absorption spectrum and, in particular, the NMR proton chemical shifts of this molecule are very difficult to reconcile with the symmetrical nuclear configuration (Dg ) suggested by the superposition of the Kekule-type resonance structures. The hypothesis of a bond-length alternation of symmetry removes this difficulty. This indicates that the resonance between Kekule-type structures should be very much impeded also in this molecule. 

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