Absorption UV-visible spectrum

The UV-visible absorption spectrum of Ru(2,2 -bipyridine)3 maximum at about 450 nm, from which the energy in volts for process XI-39 may be estimated. The standard reduction potential for the R" /R couple is about 1.26 V at 25°C. Estimate from this information (and standard reduction potentials) the potential in volts for processes XI-40 and XI-41. Repeat the calculation for alkaline solutions. 

In this work we examine the low energy UV-visible absorption spectrum of the [Fe2 ft - S2) P o- 61148) )2] complex, Figure 1, whose synthesis, structure, and properties have recently been reported. The complex contains a [Fe — S — S - Fe] core and is a structural isomer of the 2-Fe [Fe — ill — 8)2 — Fe ferredoxin. The electronic structure of the disulfide complex is, however, unknown, and can be associated with either an antifer-romagnetically (AF) coupled [Fe d ) - - Fe d )] system, or with a... 

A useful measure of the strength or intensity of the colour of a dye is given by the molar extinction coefficient (e) at its 2max value. This quantity may be obtained from the UV/visible absorption spectrum of the dye by using the Beer-Lambert law, i.e. 

Figure 19 Example of a UV-visible absorption spectrum recoded from a typical thermally degraded PVC sample. Reprinted with permission from Gerrard and Maddams [50]. Copyright 1975 American Chemical Society. 

UV-visible absorption spectrum in an aqueous bilayer solution... 

UV-visible absorption spectrum of solvent cast films... 

A UV-visible absorption spectrum of a 10 (J.M ethanol solution of a model compound (DAFc in Fig. 5) for the D moiety is shown together with that of the A-S-D triad in Fig. 16. The absorption bands between 200 and 300 nm can be clearly seen for DAFc. Qualitatively, absorption spectra for A-S-D triads in the LB films and in the 10 pM ethanol solution are similar. It is interesting to note, however, that the relative intensities of the acylated perylene band around 450 nm against the 200-300 nm UV absorption bands are different between the LB films and the ethanol solution. This difference can be attributed to orientation of the perylene moiety in the LB films in the same way as in the antenna LB films reported previously [38]. 

A yellow solution is formed when nitrous acid is added to thiosulphate ion in water84. This is believed to be due to the formation of nitrosyl thiosulphate [O3SSNOI, although this has not been isolated and even in solution decomposition is fairly rapid. The equilibrium constant for its formation Wxno is 1.66 x 107 dm6 mol 2 at 25 °C and the UV-visible absorption spectrum is very similar to that of other S -nitroso compounds85. The rate constant for its formation is very large and is believed to represent a diffusion controlled process. Thiosulphate ion does appear to catalyse nitrosation but, over the range studied... 

The lack of a clearly developed peak in the UV-visible absorption spectrum due to plasma resonance places a limit on the collective metallic behavior of the electrons in the cluster. On the other hand, the 5d -y 6s,6p interband absorption is well developed toward that of large colloidal gold particles. 

Ferrocenyl dendrimers also afford electroactive films on indium tin oxide (ITO) electrodes in the same manner as described above. UV-visible spectroelectro-chemical measurements of this modified electrodes on oxidation show changes characteristic for the formation of fenocenium cations. Thus, Figure 8 shows the UV-visible absorption spectrum of a film of 2 electrodeposited on a transparent ITO electrode, which exhibits a strong band at 260 nm and a weak absorption band centered at 600 nm, which agree with those observed for the cationic dendrimer [2 KPF j ]g in solution described above. 

Adding N-, O-, or S-atom functionalities to a PAH can cause major changes in its UV-visible absorption spectrum. For example, as seen in Fig. 10.12, addition of NO 2 groups to BaP to form the 1-, 3-, and 6-nitro isomers results in pronounced red shifts in their absorption spectra (Pitts et al., 1978). This enhanced ability to absorb solar radiation has significant implica-... 

FIGURE 10.11 UV-visible absorption spectrum of cyclopenta[ /]pyrene in cyclohexane (adapted from Karcher el al., 1985). This PAH does not fluoresce. 

Fig. 3.5.4 The UV/visible absorption spectrum of CdS formed in a 19-layer ArH LB film after 1-5 (a-e) intercalation cycles. The increase in the total absorption, the red shift in the inflection poini (minimum in the first derivative), and the increase in scatter can be seen. Inset Inflection point wavelength as a function of i/s cycles. The average size of the particles in nm, as estimated from UV/visible absorption spectra, are shown. (From Ref. 5.)...

The compound (Me3tacn)CrCl3 is a green solid that is air- and moisture-stable at room temperature. It is soluble in dimethylformamide and dimethylsulfoxide, but insoluble in water and most other common solvents. Its UV-visible absorption spectrum (DMF) shows maxima (e) at 468 (132) and 634 (111) nm. 

Steady-state UV-visible absorption spectrum of the NKX-2311/ZnO film is also shown in Fig. 1. It was found that adsorption of the dye onto ZnO and TiC>2 (data not shown) leads to the spectral blue-shift of the dye absorption by 15 and 25 nm, respectively, and slight broadening compared with the spectrum in solution. When a bare ZnO film (without dye) was excited at 355 nm with the nanosecond laser, an absorption band shown by the dashed line in the same figure was observed in the near IR region. This band is assigned to intra-band transitions of electrons in the conduction band [10], Electrons in Ti02 showed weaker absorption in the near IR region. 

The UV-visible absorption spectrum of the monoprotonated form of PLP was divided mathematically into individual bands for the aldehyde with dipolar ionic ring (+), the aldehyde tautomer with an uncharged ring (0) and the hydrate of the dipolar ion. The following fractions were estimated (Harris et al, 1976, Biochem. Biophys. Acta. 521,181-194. 

Note that in all of these situations, one can begin to unravel the excited state rate constants if measurements of i° and of i can be made. There are several ways in which this can be done. The most common one is from the decay of the emission from A, following pulse excitation. Alternatively, it has been possible in several cases to observe the UV-visible absorption spectrum of A, and the decay of this absorption again gives x° or t (see, for examples, refs. 22-26). In rare cases, it has been possible to observe the rate at which the primary photoproduct P grows in, again following a pulse excitation it should do this with the lifetime of A. 27... 

Fig. 12. (a) Structure of F430, deduced from the structure of the methanolysis product (88). (b) UV/visible absorption spectrum of F4J0 in water, concentration 10 5M. 

UV-Visible Absorption Spectrum Absorption spectroscopy Tyrosine-Tryptophan environments, presence of absorbing ligands or impurities. ... 

Changes are observed in the UV-visible absorption spectrum of 9-(4,5-dimethyl-l,3-dithiol-2-ylidene)thioxanthene during electrochemical oxidation. The absorption of the neutral molecule at 384 nm gradually decreases as oxidation to the dication occurs and new peaks appear at 325 and 408 nm (Equation 10). The oxidation potential for the single two-electron process as derived by cyclic voltametry is +0.23 V <2006CEJ3389>. 

H.C. Georg et al., Solvent effects on UV-visible absorption spectrum of benzophenone in water A combined Monte Carlo quantum mechanics study including solute polarization. J. Chem. Phys. 126, 034507-1-034507-8 (2007)... 

Lowry and Gilbert1 claimed that dimethyl tellurium iodide cyanide is formed when dimethyl tellurium diiodide and dimethyl tellurium dicyanide are mixed in ethanol. The compound was not isolated and only a UV-visible absorption spectrum was reported. 

The UV-visible absorption spectrum of the CdS nanotubes given in Fig. 2a shows a blue-shift in the excitonic absorption band to 460 nm. The blue-shift from the bulk value of 515 nm [12] is due to quantum confinement effects in the CdS nanotubes, the inner diameter of the nanotubes being less than the Bohr-exciton diameter of CdS (6 nm). Xiong et al. [13] have reported an absorption band at 459 nm for CdS nanotubes with an inner diameter 5 nm prepared by an in situ micelle-template-interface reaction. An absorption maximum around 450 nm has been reported in nanoparticles and hollow spheres of CdS [12,14], In Fig. 2b, we show the photoluminescence (PL) spectrum of the CdS nanotubes prepared by us, revealing a band centered at 610 nm. This band is due to charge carriers trapped at surface defects of the nanotubes [15,16],... 

As already noted, PuCU does not exist in the solid state however, it has been detected in the gas phase above 900 °C by its UV-visible absorption spectrum, so the equilibrium below moves to the right on heating ... 

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