Soft X-ray emission

XES, Soft x-ray emission An x-ray or electron beam Energy levels and chemical... 

With the semiconducting oxides, we expect anionic chemisorption to occur over the lattice cations, and our simple molecular orbital theory will be adequate if the conduction band is associated mainly with the cation lattice. This is certainly the case with AI2O3, where there is direct evidence in the soft X-ray emission spectra that the highest filled band is the oxygen 2p band 16). 

U Cephei (V = 6.8-9.0, P = 2.493 d) is an eclipsing binary consisting of a B7V primary and a G8DI-IV secondary component. This binary is one of the semidetached Algol systems showing soft X-ray emission which is probably associated with a hot corona surrounding the secondary component (White and Marshall 1983). 

IR, Raman, NMR, ESR, UPS, XPS, AES, EELS, SIMS) [1]. However, some industrial carbon materials such as amorphous carbon films and carbon black cannot be easily characterized from the local-structure point of view by these methods, because these materials usually take amorphous and complex structures. Recently, soft X-ray emission and absorption spectroscopy using highly brilliant synchrotron radiation [2] has been utilized to characterize various carbon materials, because information on both the occupied and unoccupied orbitals, which directly reflect the local structure and chemical states, can be provided from the high-resolution soft X-ray measurements. We have applied the soft X-ray spectroscopy to elucidate the local structure and chemical states of various carbon materials [3]. Additionally, we have successfully used the discrete variational (DV)-Xa method [4] for the soft X-ray spectroscopic analysis of the carbon materials, because the DV-Xa method can easily treat complex carbon cluster models, which should be considered for the structural analysis of amorphous carbon materials. 

Soft X-Ray Emission Spectral Analysis of Graphite Fluoride (CF)n Using the DV-Xa Calculations... 

Abstract We measured the soft X-ray emission spectra (XES) in the C and F /C-regions... 

The samples were commercially available (CF) powder and highly oriented pyrolytic graphite (HOPG) as a reference. Soft X-ray emission spectral measurements in the C and F X-regions were performed in the beamline BL-8.0.1 [9] at... 

There are three main detection modes for EAPFS within the appearance potential spectroscopy (APS) technique./31/ First, one may monitor soft-x-ray emission due to the decay of the core hole left by the primary process. This is called SXAPS-EAPFS (Figure le). Second, it is also possible to monitor Auger electrons due to the same core-hole decay, as in AEAPS-EAPFS and AMEFS-EAPFS, cf. Figure If. Third, one may measure the remaining total intensity of... 

Fig. 3.12. Measurements with high time resolution ( 4(is) of the MHD activity (measured with Mirnov coils), pedestal temperature (Te,pea) and soft X-ray emission collapse, and outer divertor Da emission and inner divertor X-ray bremsstrahlung (from hot electron impact) during a Type I ELM in JET. The collapse of Te,ped, pedestal soft X-ray emission and the increase of the inner divertor bremsstrahlung emission occur over a time interval of 200-300 ps, similar to the period of large MHD activity [27]...

Fig. 3.13. Time duration of the edge plasma collapse phase determined from the edge soft X-ray emission for a large range of JET Type I ELMy H-mode plasmas [27]...

Nithianandam, V. J., and S. E. Schnatterly (1988). Soft x-ray emission and inelastic electron scattering study of the electronic excitations in amorphous and crystalline silicon dioxide. Phys. Rev. B38, 5547-53. 

Triguero L, Luo Y, Pettersson LGM, Agren H, Vaterlein P, Weinelt M, Fohlisch A, Hasselstrom J, Kaiis O, Nilsson A (1999) Resonant soft X-ray emission spectroscopy of surface adsorbates Theory, computations and measurements of ethylene and benzene on Cu(llO). Phys Rev B 59 5189... 

It should be mentioned, that soft X-ray emission of PSR 1929+10 can be due to polar caps or due to non-thermal mechanism. 

The cubic modification (3C-SiC) is the only SiC with zinc blende structure. The band structure of 3C-SiC has been calculated theoretically by Kobayashi [1], and estimated from optical absorption and reflection [6], luminescence [7], soft X-ray emission [8] and X-ray photoelectron [9] spectra. 

Photoelectron spectroscopy provides a useful (because direct) tool for studying the valence-band structure of solids. It is unlike soft x-ray emission spectroscopy where one must contend with transitions (to inner shells) that are constrained by selection rules and where one must take into account the character of the shell to which the transitions occur. In photoelectron spectroscopy, any of the occupied states in the band can be examined by ejecting the band photoelectrons. Thus, the photoelectron spectral shape essentially reflects the structure of the occupied band itself. 

Wiech and Zopf (1972) measured the soft X-ray emission spectra of a-Si, Eastman (1972) and Ley et al (1972) UV and X-ray photoemission from a-Si and a-Ge and obtained information about the state densities in the valence band. They observed two bands as predicted by Thorpe and Weaire (1971) instead of the three bands observed in crystals (Figure 4.28). This experimental result agrees with the above mentioned considerations of Joannopoulos and Cohen (1972). 

Nordgren, J., Gians, P, and Wassdahl, N. 1991. Progress in ultra-soft X-ray emission spectroscopy. Phys. Scr. 

Boron nitride, cubic BNcub g, ind r i5v to Xlc 6.2 Soft-X-ray emission spectroscopy... 

A sulphur L-shell XPS spectrum showing valence orbitals of the SFg molecule is shown in Fig.5.15. An ultra-soft X-ray emission spectrum for the same molecule is also included. The figure illustrates how the different selection rules for X-ray emission and XPS lead to complementary information for the interpretation of the valence orbital structure of the molecule. 

J. Nordgren Ultra-soft X-ray emission spectroscopy - a progress report, in Proc. 14th Int l Conf. on X-Ray and Inner Shell Processes. J. Physique C 9, Suppl.l2 (1987)... 

---