He photoelectron spectra

Kirnura, K. Katsumata, S. Achiba, Y. Yamazaki, T. Iwata, S. Handbook of He] Photoelectron Spectra of Fundamental Organic Molecules. Japan Scientific Societies Press Tokyo Halsted Press New York, 1981. 

The He photoelectron spectra of thiazole, benzothiazole, and naphtho[l,2-<( thiazoles have been reported <93JST(296)115>. This study confirms most of earlier results <84CHEC-I(4)240>. The assignments of ionization potentials to molecular orbitals have been made on the basis of semiempirical SCF MO calculations. 

Fig. 7. (He) Photoelectron spectra of H2S, (R3SiCH2)2S and (RsSHjC-S-CHj with Koopmans assignment (see text)...

The He I ultraviolet photoelectron spectra of Kr and Xe appear similar to that of Ar but the ionization energy decreases and the spin-orbit coupling increases with increasing atomic number, as illustrated by the data in Table 8.1. 

The He(Ia) photoelectron spectra of the parent heterocycles have been the subject of much study. Initially the assignment of the ionization energies to appropriate occupied molecular orbitals was confused by the unexpected reversal in the sequence of the two highest occupied MOs in tellurophene relative to the other heterocycles. The reported values are compared in Table 24. The assignments are based upon comparisons with the spectra... 

The same group has published two articles on indazoles [indazole (36), 1-methyl- (106) and 2-methyl-indazole (107)]. The He-I and He-II spectra have been obtained and satisfactorily interpreted by means of ab initio LCGO calculations (78JST(43)33, 78JST(43)203). The PE spectra support the conclusion (Section 4.04.1.5.1) that the 1//-tautomer is by far the more stable. X-Ray photoelectron spectra of some pyrazole and pyrazoline derivatives have been reported (83MI40400). 

Furlani C, Cauletti C (1978) He(I) Photoelectron Spectra of d-metal Compounds. 35 119-169... 

Very recently, photoelectron spectra have been recorded for disilenes 1,3, and 25.54 Consistent with the electronic spectra, the lowest ionizations were assigned to the Si=Si 7r-orbital. The He(I) photoelectron spectrum for 1 is shown in Fig. 4. The low-energy ionization appears at 7. 53 eV. The more intense, higher energy bands were shown to be due to ionizations from mesityl 7r-orbitals by comparison with the photoelectron spectra of model compounds without a Si=Si bond. 

The He(I) photoelectron spectra of compounds 9,10,11,12, 2, 2-H2, 23,23-H2, and 5059) and of 26-29 60> have been recorded. The spectra of peroxides 9, 2, and 23 have been measured independently by another group and the results are in good agreement with ours data for compounds 6,2a, and 20 were also reported 28). 

The He(l) photoelectron spectra <1997JMT(392)21> of ATQ and TATCD were measured and interpreted by means of ab initio outer valence Green function calculations (OVGF). These gave an overall consistent agreement with the main features in the spectra, in particular of the n (N) bands. 

Fragalia and co-workers have reported the details of the He(I) and He(II) excited photoelectron spectra of Cp2Ti(CO)2 and concluded that evidence exists for significant backbonding between the Ti 3d orbitals and empty carbonyl v orbitals. Further, there is no evidence of important overlap between Ti and Cp orbitals. A small electrostatic perturbation of the Cp ligands is caused by the titanium atom (85). Bohm has described an elaborate study of the low energy PE spectrum of Cp2Ti(CO)2 (1) by means of semiempirical MO calculations (86). 

Figure L He (I) photoelectron spectra of the lowest energy bands of Me%Hg, EtHgMe, -PrHgMe, and t-BuHgMe.

I would like to make a few comments regarding the photoelectron spectra presented by Dr. Sattelberger. In referring to his spectrum of W2, he has assigned the ionization band... 

K. Kimura, S. Katsumata, Y. Achiba, T. Yamazaki and S. Iwata, Handbook of He I Photoelectron Spectra of Fundamental Organic Molecules, Japan Scientific Press, Tokyo, 1981. 

FIGURE 5. The He I photoelectron spectra of compounds 1-4 (1 = EtrGe 2 = Et3GeH 3 = Et2GeH2 4 = EtGeH3). Reproduced by permission of Elsevier Science from Reference 38... 

FIGURE 6. The photoelectron spectra of Me Snt U. Close-up of the 4d region of the He II spectrum. Reproduced by permission of The Royal Society of Chemistry from Reference 57... 

The He I and He II photoelectron spectra of tetravinylstannane Sn(CH=CIl2)4 were studied by Novak and coworkers87. They assumed a rather weak interaction between the vinyl groups, and between them and the central tin atom. 

The photoelectron spectrum of 12 was observed and the measured ionization energies were compared with the orbital energies calculated for the parent tetrasila[2.2]paracyclophane (21). The He I photoelectron spectra of 1 was recorded to have a broad first band at 8.1 eV that was well separated from other bands (22). The first bands of 12 are remarkably different from those of 1. A shoulder at 7.8 eV and a broad band centered at 8.3 eV was observed. A comparison between the band sequence of 12 and 1 based on both empirical and quantum chemical studies shows a smaller through-space and a larger through-bond interaction for 12. The through-bond interaction between the b3u (cr) orbital and the corresponding tt orbital yielded a different orbital sequence in 12 as compared to 1 (Fig. 6). 

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