Photoelectron spectrum allene

Fig. 4. The X E band in the photoelectron spectrum of allene. (a) Calculated spectrum including two (r)4+ e) Jahn-Teller active modes, (b) Experimental high-resolution spectrum (reproduced from Ref. 100).

The property of interest here is a spectrum, either an absorption spectrum (pyrazine) or photoelectron spectrum (butatriene and allene). The spectrum [Pg.596]

Allen and Martin (1982) and Lavagna et al. (1982, 1983) proposed that the y-a transition in Ce was related to the Kondo effect. Since Kondo systems have densities of states with two peaks, one very close to the Fermi level and one below, this offered a possible explanation of the two peaks in the photoelectron spectra, assuming that the photoabsorption process would transfer the structure in the density of states to the emitted spectrum. Detailed calculations of a photoelectron spectrum were not, however, carried out. The Kondo (or Abrikosov-Suhl) resonance in the density of states can be obtained from the Anderson Hamiltonian in the limit U CO (Lacroix 1981). For a Fermi level in the center of a valence band of width 2D and a constant density of states coupled by a constant matrix element V to an Nf-fold degenerate localized level at energy Sf below two peaks can arise in the density of states of the coupled system at low temperatures if is not too small. As... 

Subsequently, Grunthaner reexamined the ESCA spectrum of the 2-norbornyl cation on a higher-resolution X-ray photoelectron spectrometer using highly efficient vacuum techniques.884 The spectrum closely matches the previously published spectra. Furthermore, the reported ESCA spectral results are consistent with the theoretical studies of Allen and co-workers885 on the classical and nonclassical norbomyl cation at the STO-3G and STO-4.31G levels. Using the parameters obtained by Allen and co-workers, Clark and co-workers were able to carry out a detailed... 

The allenes bearing four tert-butyl or four trimethylsilyl groups at the terminal carbons react in methylene chloride with antimony pentachloride. The cation radicals formed contain an unpaired electron delocalized along the neighbouring -rr-bonds. The conclusion is based on the analysis of 1H, 13C, and 29Si ESR spectra (Bolze et al. 1982) as well as on photoelectron spectra (Elsevier et al. 1985 Kamphius et al. 1986). These data have found corroboration in a recent study (Werst Trifunac 1991). The tetramethylallene cation radical spectrum was observed by fluorescent-detected magnetic resonance. The well-resolved multiplet due to this cation radical consists of a binomial 13-line pattern owing to 12 equivalent methyl protons. This is in full accord with Scheme 3-60. 

More recently, substituted transient thioxosilanes have been obtained by a retro-ene reaction according to Scheme 6.3. In this study, the thermolysis of several thiosilanes such as 9a and 9b (Scheme 6.3) was examined using both high-resolution mass spectrometry (HRMS) and photoelectron spectroscopy (PES). While monomeric (/-Pr)2Si=S (10b) was obtained from 9b and identified independently by both methods employed, 10a was not observed in the mass spectrum of the thermolysis products of 9a. Moreover, the detection of monomeric 10a by its PE spectrum was hampered by strong bands due to allene and undecomposed precursor obscuring bands assumed to stem from lOa.PH... 

Although the bulk properties of 5f-electron heavy fermions are entirely similar to those of 4f-electron heavy fermions (see, for example, Stewart 1984), the respective photoelectron spectra appear substantially different (an excellent review of the early work is given by Allen 1992). Unlike the triple-peaked 4f spectra in Ce compounds (the /° and / states within the SIM interpretation), measurements at the 6d absorption edge where the 5f signal is enhanced, generally yield a rather broad, triangular shaped spectrum... 

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