Experimental photoelectron

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,... 

Fig. 2. Left experimental photoelectron spectra as a function of the delay time r. Right Measured photoelectron spectra as a function of the laser intensity at a fixed delay time.

Comparison of theoretical data with experimental spectra led also to the identification of compounds which have germanium-nitrogen double and triple bonds. Foucat et al. report about the results of flash vacuum thermolysis of substituted germacyclopentenes and DFT (B3LYP) calculations of model compounds of possible reaction products114. The authors took the experimental photoelectron (PE) spectra and compared them with... 

A spectacular example of the unusual shapes possible for bare clusters is the recent development of naked B wheels and other planar shapes generated by calcula-tional chemistry and supported by quantitative fits to experimental photoelectron spectroscopic data. Two examples, [Bg]2- and [Bg]-, are shown in Figure 2.28... 

The role of polarizability of Cl" in the energy and geometry of the clusters has been studied by Dang and Smith [115]. In the cluster with six water molecules, they observed that the increase of CT polarizability from zero to its experimental value changes the structure from a symmetric one to a surface-type asymmetric one, with all waters on one side of the ion. Results on the cluster, however, only moderately agree with experimental photoelectron spectroscopy data and are unable to reproduce the minimum energy configurations predicted by Combariza et al [200] with ab initio calculations. The latter data are better reproduced with a smaller polarizability of C1 . 

We are focusing on the five lowest electronic states of the benzene cation and its fluoro derivatives, namely the mono-, di- (three different isomers) and tri- (1,2,3-isomer) fluorobenzene cations. These states lie, for all six cations, in the energy range from 9 to 13-14 eV above the electronic ground state of the respective neutral species. They give rise to the low energy band systems of the experimental photoelectron spectra [70]. 

The X-A-B-C coupled state vibronic spectra are calculated by including the 24 vibrational modes mentioned above, by propagating WPs employing the MCTDH scheme. The theoretical results obtained are plotted in Fig. 8 along with the experimental photoelectron spectroscopy results of [101]. It can be seen that theoretical results are in excellent accord with the experimental findings. 

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. 

Pig. 8. Cuts of the calculated photoelectron spectrum at delay times (a) Ofs, (b) 50 fe, and (c) 300 fs, assuming probe pulses of 100 fe duration. Shown are the contributions pertaining to the Si (long dashed lines), the (short dashed lines), and the cross terms (thin full lines), respectively, as well as the total spectrum (thick full lines), (d) The experimental photoelectron spectra at delay times 0 fe (full line) and 300 fe (short dashed... 

One of the earliest applications of computational methods to supramolecular phenomena was a theoretical investigation into the widely acknowledged size selectivity of crown ethers for particular alkali metals (Figure 7). As early as 1975, ST0/3G quantum mechanical simulations of [Li(12-crown-4)]+ had been attempted, to be followed by 18-crown-6 complexes of Na+, K+, and NH4+ in 1979. Yanabe s calculations, using the semiempirical CNDO/2 method, gave a good correlation with experimental photoelectron spectra and, importantly noted that ... 

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 ...

Among the band calculations, there were two attempts, by Ivashchenko (1984) and Schalder and Monnier (1989), to study the influence of structural defects on the electronic structure of solid solutions. Ivashchenko used the APW-LCAO-CPA method for analysis of the DOS distribution in the ZrC jN D (x + y + z = 1) alloy. It was found that metallization of the alloy takes place as z increases. Some Hf carbonitrides with a variable number of p atoms and cation and anion vacancies were studied by Schalder and Monnier (1989) making use of the relativistic KKR-GF method. Reasonable agreement was obtained between the calculated and experimental photoelectron spectra. It was shown that the presence of defects in the solid solutions leads to the formation of additional vacancy states (Fig. 5.12), which are typical for binary phases (Chapter 4), and to partial charge polarisation towards metallic centres. The latter effect is more pronounced for C vacancies (see Table 5.1). One of the most interesting conclusions of this paper was the establishment of the nonmonotonic variation of the N(Ep) in the series HfC HfCj,Nj HfN (Table 5.1). 

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...

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