Ground states spectra

The equilibrium ground-state spectra of the parent six-coordinate and deoxy five-(or four-)coordinate species were obtained using a Tungsten lamp placed before the I /I beam splitter. Earlier work in our laboratory (3,4) has established that the experimental spectra of transient protoproducts can be resolved as they sequentially evolve during the dissociation process. At relatively long delays > 20 psec after excitation, the spectrum of the stable photoproduct... 

Figure 4, Ground state spectra of the four-coordinate form of 1-ET and 1-ET-CO 6-coordinate (solid) and 4-coordinate (dotted),...

We elected to study coherent up-pumping dynamics in solution-phase metal-hexacarbonyl systems because of their strong vibrational infrared absorption cross sections, relatively simple ground-state spectra, and small (ca. 15 cm ) anharmonic overtone shifts. It was felt that these systems are ideal candidates to demonstrate that population control could be achieved for polyatomic species in solution because the excited state population... 

A 10 M solution of methyl vlologen (MV ) did not have slgnlflcant ground or excited state absorbance from 350 nm to 750 nm. A 10 M solution of methyl vlologen In Aldrich HSX had ground state spectra characteristic of humic substances before and after laser Irradiation. A transient absorption spectrum of the above solution measured under the standard experimental condltio described previously showed a spectrum similar to that of MV reported In the literature (31)., 2 Figure 7. These data show evidence of Interaction between MV and the humic substance via a photoprocess. 

The Eq. (13) and (17), since their parameters refer to the ground state equilibrium configuration of the nuclei Q = 0 for any coordinate i, then can be put into relation to the ligand field parameter 10 Dq derived from the ground state spectra by... 

The absorption properties of Pis (ground state spectra and molar extinction coefficients, a) play a decisive role in the photoinitiation step as (i) the PI absorption spectrum has to match the emission spectrum of the light source and (ii) the polymerization rate Rp is directly connected with the amount of light absorbed. The development of Pis lies on the design of new chemical structures and the synthesis of new derivatives of... 

Fig. 3 Difference spectra of the cross-sections (

Mutant Construction. Metal and Pigment Stoichiometry, and Room Temperature Ground State Spectra... 

At 70% methanol (30% D20), very little quenching is observed and this correlates with the formation of a new band in the ground state spectrum in methanol/water mixtures as shown in Figure 14.3. 

The ground state spectrum in Figure 5 exhibits the typical features of the Raman spectrum of a bipyridine complex (40,51,52). Seven relatively intense peaks dominate the spectrum. These may be approximately described as the seven symmetric C-C and C-N stretches expected of bipyridine in any point group wherein the two pyridine rings are related by a symmetry element. 

Figure 3. (A) Absorption changes in the BPh region at 30 ps and 1.6 ns at 5 K. (B) Difference between the 30-ps and 1.6-ns spectra. (C) Ground-state spectrum of the same PVA film in this region at 5 K. Reproduced with permission from Ref. 35.

The long lifetimes and high redox potentials of a range of ruthenium(II) complexes and in particular [Ru(bpy)3] " have important consequences for their use as photoactive redox catalysts. This area of research is extremely active and we now focus on the decay of the excited state of [Ru(bpy)3] + ( [Ru(bpy)3] " ) and its quenching. Braterman et al. have described the electronic absorption spectrum and structure of the emitting state of [Ru(bpy3] +, and the effects of excited state asymmetry. The effects of solvent on the absorption spectrum of [Ru(bpy)3] " have been studied. In H2O, MeCN and mixtures of these solvents, the value of e(450 nm) remains the same ((4.6 0.4) x 10 dm mol cm ). The ground state spectrum is essentially independent of... 

Much of the work has been focused on what is the hydrated electron and what gives rise to the spectrum. These experiments have suggested that the spectrum of the hydrated electron cannot be clearly shown to be inhomogeneous, i.e. made up of multiple components that do not interconnect on the experimental lifetime. Theoretical studies had suggested that the ground-state spectrum would be made up of three s-p transitions of different energies that would interconvert on the experimental time scale however, this was not clearly shown by the experimental work. ... 

However, since the light-induced difference-minus-ground-state spectrum of [P%7o a 1 shows a bleaching of one of the bacteriopheophytins (BPh) near 546 nm, the charge recombination of the primary radical pair would yield a very similar spectral profile and its time constant would be of similar magnitude as the one observed (Shuvalov and Parson, 1981). Thus it seems still premature to make a decisive statement on the fast transient component observed as an increase in absorption at the wavelength of the spheroidene triplet-triplet absorption band at 550 nm. 

The incorporation of the functionalized fullerene into a host molecule, such as a y-cyclodextrin or surfactants is an elegant way to bypass the aggregation of C6oC(COO )2-As demonstrated in studies with [60]fullerene this host can accommodate only a single fullerene molecule, which still has access to the solvent phase. The ground state spectrum of this guest-host complex shows the same narrow bands as, for example, monomeric C6oC(COOEt)2 or Cgo/Y-CD and clearly differs from the presumed CeoCfCOO )2 n cluster. 

The energy level spectrum of the hamionic oscillator is completely regular. The ground state energy is given... 

The Hamiltonian provides a suitable analytic form that can be fitted to the adiabatic surfaces obtained from quantum chemical calculations. As a simple example we take the butatriene molecule. In its neutral ground state it is a planar molecule with D2/1 symmetry. The lowest two states of the radical cation, responsible for the first two bands in the photoelectron spectrum, are and... 

To define the state yon want to calculate, you must specify the m u Itiplicity. A system with an even ii n m ber of electron s n sn ally has a closed-shell ground state with a multiplicity of I (a singlet). Asystem with an odd niim her of electrons (free radical) nsnally has a multiplicity of 2 (a doublet). The first excited state of a system with an even ii nm ber of electron s usually has a m n Itiplicity of 3 (a triplet). The states of a given m iiltiplicity have a spectrum of states —the lowest state of the given multiplicity, the next lowest state of the given multiplicity, and so on. 

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