Vanadium oxide, energy band

As shown in Fig. 8, the vibrational bands are clearly resolved in the photoluminescence spectrum of vanadium oxide supported on Vycor glass 33, 34, 36-38). The vibrational separation of about 1040 cm is in good agreement with the energy of the V=0 stretching vibration of the ground state of the vanadyl group of the oxide as measured by IR or Raman spectroscopies. 

Figure 20 shows the second-derivative spectrum of the photolumincs-cence shown in Fig. 19. The well-resolved fine structure indicates that the energy gap between the (0 -> 0) and (0 - 1) vibrational transition bands is 1040 cm in good agreement with the vibrational energy of the surface V=0 bond obtained by IR or Raman measurements. These findings indicate that the photon energy absorbed by the vanadium oxide/SiOa catatyst is mainly localized on the V=0 surface bonds.The Raman spectrum of the anchored vanadium oxide/Si02 catalyst observed at 78 K exhibits a peak at 1050 cm in good agreement with the results obtained by Went...

The electronic stmcture of bulk vanadium oxides is determined to a major extent by the amount of d electron occupation in the vanadium ions. In the ideal three-dimensional periodic bulk, electrons are described by Bloch states with energy dispersions reflected in band stmctures and corresponding densities of states (DOS). These quantities can be calculated with high accuracy by modem band stmcture and total energy methods based on the density functional theory (DFT) method. 

VP Zhukov, VA Gubanov, O Jepsen, NE Christensen, OK Andersen. Calculated energy-band structures and chemical bonding in titanium and vanadium carbides, nitrides and oxides. J Phys Chem Sohds 49 841, 1988. 

The conductor catalysts are the metals (silver, platinum, vanadium, iron, etc.) and have the property of chemisorption by electron transfer. The semiconductor catalysts are the oxides, such as NiO, CU2O, and ZnO. These materials have the capability of interchanging electrons from the filled valence bands in a compound when sufficient energy is provided,... 

Changes in the relative intensities and emission energies of X-ray emission bands with formal oxidation state of vanadium in a range of its compounds have been rationalized in terms of variations in 4p character in valence-shell MOs there appears to be a negligible contribution from 3d character. ... 

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