Experimental photoelectron spectrum

The UF6 molecule has also been studied extensively using a more elaborate method, namely configuration interaction, to assign the experimental photoelectron spectrum (de Jong and Nieuwpoort 1998). The qualitative analysis of chemical bonding exhibits that the U-F bond is more ionic in the relativistic framework (de Jong and Nieuwpoort 1998). The 6s orbital of uranium remains atom-like in the molecule due to relativistic contraction and does not contribute to chemical bonding, while it contributed in nonrelativistic Hartree-Fock theory. 

Model 1. Simulated Experimental Photoelectron Spectrum of Neon. 

Fig. 8 - Musical transcription of the experimental photoelectron spectrum of phosphabenzene. The third note differs from that given in Ref. [17].

Fig. 6.1 Comparison of the experimental photoelectron spectrum of butatriene with the full theoretical result and the one obtained in the Condon approximation with uncoupled PESs (from left to right). The band V in the left panel was termed mystery band ...

Figure 1 Schematic drawing of the experimental photoelectron spectrum of CNCN (A) and calculated spectra of CNCN (B), CNNC (C), and NCCN (D). The calculations are discus.sed in detail in Ref. 67...

Figure 4 (a) Calculated and (b) experimental photoelectron spectrum of benzene, reflecting the vibronic structure of the electronic... 

Figure 2. Experimental photoelectron spectrum of Wang et al (Reproduced with permission from reference (3), Copyright 1997 American Institute of Physics.)...

Figure A3.7.6. Photoelectron spectrum of. Here the F is complexed to para-R - Solid curve experimental results. Dashed curve simulated spectrum from scattering calculation on ab initio surface.

Figure 29 compares the calculated40 and experimental photoelectron spectra. Figure 29(a) compares the calculated spectrum from the ground state of HsO with the experimental spectrum that was obtained with a zero angle between the laser polarization and direction of electron detection,... 

Robin et al.162 investigated the photoelectron spectrum of unsubstituted cyclo-propenone and interpreted its results with the aid of Gaussian-type orbital calculations of double-zeta quality for the electronic ground state using the experimentally established133 geometry of cyclopropenone. 

Energy Levels for Hole Injection. For the hole conductor TPD (6), measurements are available from different groups that allow a direct comparison of different experimental setups. The ionization potential that corresponds to the HOMO level under the assumptions mentioned above was measured by photoelectron spectroscopy to be 5.34 eV [230]. Anderson et al. [231] identified the onset of the photoelectron spectrum with the ionization potential and the first peak with the HOMO energy, and reported separate values of 5.38 and 5.73 eV, respectively. The cyclovoltammetric data reveal a first oxidation wave at 0.34 V vs. Fc/Fc+ in acetonitrile [232], and 0.48 V vs. Ag/0.01 Ag+ in dichloro-methane [102], respectively. The oxidation proceeds by two successive one-electron oxidations, the second one being located at 0.47 V vs. Fc/Fc+. 

An upsurge of interest in the N-methylborazines in the early 1970 s was coupled with a convenient method of synthesis and purification for these compounds The photoelectron spectrum of N-trimethylborazine has been reported. Table 6 summarizes the theoretical and experimental data comparing the location of the molecular orbitals of N-trimethylborazine with those of borazine. The HOMO is predicted and observed to be an e" (w) orbital as in borazine The methyl substitution on nitrogen destabilizes the e" and the a2 jr-orbitals, but does not signiBcantly effect the e (a) orbital. The result is a lowering of the ionization potential for electrons in the two TT-orbitals. This effect, predicted in the dieoretical calculations, was also verified experimentally. 

SF-OD level with the basis set composed of a cc-pVTZ basis on carbons and a cc-pVDZ basis on hydrogens). These energies are very close to the MRPT values (26) of 0.72 and 0.83 eV (for the 1 fi and 1 Ai states, respectively). With regard to experiment, the lowest adiabatic state, 1 B, has not been observed in the photoelectron spectrum (40) because of unfavorable Frank-Condon factors. The experimental adiabatic energy gap (including ZPE) between the ground triplet state and the VA state is 0.70 eV. The estimated experimental >s 0.79 eV, which is 0.15 eV lower than the SF-OD estimate. 

Experimental confirmation of the order of MO energies for the water molecule is given by its photoelectron spectrum. Figure 5.13 shows the helium-line photoelectron spectrum of the water molecule. There are three ionizations at 1216, 1322 and 1660 kJ mol1. A fourth ionization at 3107 kJ mol-1 has been measured by using suitable X-ray photons instead of the helium emission. That there are the four ionization energies is consistent with expectations from the MO levels for a bent C molecule (see Figure 5.12). 

The VSEPR assumption that there are four identical localized electron pair bonds in the four C-H regions, made up from sp3 hybrid carbon orbitals and the hydrogen Is orbitals, is not consistent with the experimentally observed photoelectron spectrum. The MO theory is consistent with the two ionizations shown in the photoelectron spectrum of CH4 and implies that the bonding consists of four electron pairs which occupy the la, and It, five-centre MOs. 

Evidence for the reverse process, donation of electron density from the nucleophilic dimer atom to an electron-deficient molecule, also exists. Konecny and Doren theoretically found that borane (BH3) will dissociatively adsorb on Si(100)-2x1 [293]. While much of the reaction is barrierless, they note an interaction between the boron atom and the nucleophilic atom of the Si dimer during the dissociation process. Cao and Hamers have demonstrated experimentally that the electron density of the nucleophilic dimer atom can be donated to the empty orbital of boron trifluoride (BF3) [278]. XPS on a clean Si(100)-2 x 1 surface at 190 indicates that BF3 dissociates into BF2(a) and F(a) species. However, when BF3 is exposed on a Si(100)-2 x 1 surface previously covered with a saturation dose of trimethylamine, little B-F dissociation occurs, as evidenced by the photoelectron spectrum. They conclude that BF3 molecularly adsorbs to the nucleophilic dimer atom and DFT calculations indicate that the most energetically favorable product is a surface-mediated donor-acceptor complex (trimethylamine-Si-Si-BF3) as shown in Figure 5.19. 

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