Band spectra, origins

The band spectrum of chlorine in the visible and near ultra-violet is well known from the work of Kuhn8 and others. Absorption from at least the first five vibrational levels of the normal molecule is observable. One can say from which particular vibrational levels the absorption of chlorine in the above regions at ordinary temperatures originates, and the energy of these levels is known. This is sufficient to determine the temperature coefficient of such absorption. Indeed it is partly by a process the reverse of this that the allocation of absorption to the various vibrational levels is accomplished. And so from the positions of the four... 

However, in Ref. 59 also the first valence band spectrum of U has been measured by UPS, and shows a very sharp and, compared with Th, about 10 times more intense 5f peak at 0.3 eV below Ep. Thus the UPS peak at 0.75 eV and the XPS 0.6 eV peak for Th metal may be attributed to the same origin, namely 6d, as suggested by density of state calculations, the small shift between the two being induced by the different contribution of a possible 5 f tail in the UPS and XPS spectra. 

It was noted in Ref. 12b that such important physical characteristic exists as elasticity of the spatial H-bond network, which is usually employed [15, 16, 19] for calculations of water spectra. As is intuitively clear, this elasticity should be somehow related to the R-band spectrum, since the stretching vibration, determined by the H-bond elasticity, is believed [16, 35, 51] to present the origin of this band in water. As a basic mechanism, one could regard an additional power loss due to interaction with the a.c. field of the H-bond vibrations. However in Ref. 7, as well as in Ref. 12b, a physical picture relating the CS well to bending vibrations was not established. 

Fig. 38. The agreement between simulated and experimental CD spectra for the PD complex was very good after a red-shift of 0.25 eV was applied to the excitation energies. Analysis of the computed spectrum showed the intense bands to originate predominately from n-to-n transitions within an extended n framework of the phosp-hole-helicene ligands. Unlike initially expected, the various bands in the CD spectrum cannot be assigned to transitions centered separately on the helicene and phosphole moieties, respectively. The experimentally measured molar rotation of the Pd complex was 23.1 103 deg cm2 dmol 1 2% in dichloromethane. For an analogous Cu complex it was 13.1 103 2%, a staggering 104 deg cm2 dmol 1 lower.

Fig. 3. Emission spectra of Pd(2-thpy)2 (a) in an n-octane Shpol skii matrix (line spectrum) and (b) in butyronitrile (broad band spectrum) at T = 1.3 K, Aexc = 337.1 nm (N2-Laser). The energies of the vibrational satellites are specified relative to the electronic origin at 18,418 cm f The structures marked by asterisks on the high energy side of the electronic origin result from other sites and vanish with a site-selective excitation, e.g. at 19,113 cm (18,418 cm i -1-695 cm vibrational satellite). Concentration of Pd(2-thpy)2 10 mol/1. Note Fora better comparison, the broad band spectrum is shifted by 200 cm to lower energy. (Compare Ref. [56])...

The effective masses of electrons and holes are estimated by parabolic approximation a large curvature corresponds to a small effective mass and a small curvature corresponds to a large mass. With this band concept, light absorption and luminescence are interpreted as follows Light is absorbed by the transition from valence band to conduction band. Therefore, the broadening of the absorption spectrum originates basically from the one dimensionality of the joint density of states, which is described by (E - g) . Excited electrons and holes relax to the bottom of the bands and then recombine radiatively. Therefore, the photoluminescence of the spectrum is very sharp. The energy difference between two peaks is called the Stokes shift. 

The second excited singlet state, which generates a banded spectrum with its origin at 168.8 nm , has been assigned to the Rydberg transition... 

We also observe a negative band at 190 nm in the solution spectrum of pullulan (Table II), but at much reduced intensity relative to amylose. We take this band to originate in the same local conformation responsible for the low energy dichroism in amylose. The intensity, however, is modified by the presence of l->6 linkages between repeating sequences of maltotriose. 

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