ESCA investigations of Group IV derivatives. Part II. Binding-energy predictions for bromo- and iodo-silanes and -germanes

Abstract

Chem. 54, 3876 (1976). Core-level binding energies of all atoms are reported for the bromo(methy1)-silanes and -germanes Me,MBr4-, (M = Si, Ge; n = 0 + 3) and the iodo(methy1)-silanes and -germanes MenMT4-, (n = 2, 3). Measured binding energy shifts correlate well with values predicted from atomic charge calcuIations using an electronegativity-equilisation procedure. JOHN E. DRAKE, CHRIS RIDDLE, H. ERNEST HENDERSON et BORIS GLAVIN~EVSKI. Can. J. Chem. 54, 3876 (1976).On rapporte des Cnergies de liaisons au niveau du noyau pour tous les atomes des bromornCthyl silanes et germanes Me,MBr4-, (M = Si, Ge; n = 0 + 3) et des iodomkthyl silanes et germanes Me,(M14-, (n = 2, 3). I1 y a une bonne corrklation entre les diplacements mesurCs pour les Cnergies de liaisons et les valeurs que l'on peut prCdire 2 partir des calculs de charge atomique en faisant appel a une procedure d'egalisation des Clectronegativites.[Traduit par le journal]In Part I (1) we reported core-level binding energies for two series of compounds, Me,M-C4-, and Me3MX (n = 0 + 4, M = Si or Ge, X = F, C1, Br, I). Binding energies for each atom in every compound were correlated with the partial charges on those atoms. The charges were calculated using the electronegativity-equalisation method of Huheey (2) which, in turn, is based on the Hinze-Jaffk method (3-5). We introduced the concept of allowing for s-orbital participation in the bonding orbital of the halogen atom, designating the method EESOP (electronegativity-equalisation with s-orbital participation).Because excellent correlations were obtained for the Me,MCl4-, series, we have used the related plots (Fig. 1) as established reference bases for the series Me,MX4-, (X = Br, I) reported in this paper. Thus, the partial charges on carbon 6c, germanium, aGe, silicon, as,, bromine, bBr, and iodine, 61, are calculated by our EESOP method. Then the previously established correlations (Fig. 1) are used to read off a predicted binding energy for each of the EESOP-calculated partial charges. Therefore, all of the halogenoseries MenMX4-,, M = Si, Ge; X = C1, Br, I, are assumed to obey the same linear relationship between partial charge and binding energy. These calculated binding energies are tabulated together with the experimental binding energies in Tables 1 and 2. As we found previously, by allowing for 'The experimental binding energies of C Is and I 3dj/? are corrected relative to Ar 2pi/2 = 248.63 eV (1 I), uncertainty 10.05 eV; those of Ge 3d and Br 3d5,'r are reported relative to Ne 2s a t 48.47 e V (I 1 j, uncertainty 10.05 eV. tPartial charges, 6, calculated by EESOP (1) assuming that germanium is using sp3 hybrid orbitals, xo, = 8.07 + 6.82aG,; that the carbon atom is treated as an 'unbonded tetrahedral carbon atom' using xc = 7.98 + 13.276c; and that there is 16% and 19% s-character on bromine and iodine respectively, using X B~ = 9.98 + 9.1 laBr and x , = 9.54 + 8.296,.$Binding energies are calculated by reference to the plots of BE(expt.) us. 6 for the chloro(methyl)germanes assuming that...

ESCA investigations of Group IV derivatives. Part III. Binding energies for methyl substituted disilyl and digermyl chalcogenide series

“…With few exceptions, all columns show the same trend. This is exactly as we found for the Me,GeX,-, (X = C1, Br, I) series (1,2).…”

“…Indeed, if the s-orbital participation is only ca. 5% greater for C1 than for Br and a further 3-5% greater for Br than for I, then the similarity of binding energies of the Me,MX3-, series can be explained (1,2). It seems reasonable to assume a similar argument applies to the Group VI B elements.…”

Dissociative Multiple Ionization following Valence, Br(3d), and Si(2p) Inner Shell Photoexcitation of SiBr4 in the Range of 30−133 eV

“…To assign the discrete excitations around the Si(2p) edge, we used the ab initio calculation result by Bodeur et al 2 on the term values of PBr 4 + which is a counterpart of the core-excited SiBr 4 in the view of the equivalent ionic core virtual orbital model (EICVOM), 14,34 although the Si(2p) electrons may not effectively screen the nuclear charge as in the case of the Si(1s) electrons. The binding energy of Si(2p 1/2 ) is estimated to be 110.2 eV from the reported IP value for Si(2p 3/2 ) 109.6 eV, 35,36 and the spin-orbit splitting 0.6 eV. 11-13 Hence the excitation energy corresponding to Si(2p 1/2 )-to-σ(a 1 )* can be estimated as 103.6 eV from the reported term value of 6.60 eV.…”

Binding energy of 2p-electrons of silicon atom. Substituents effects in Si-centered cation-radicals

“…Actually it follows from numerous publications [1][2][3][4][5][6][7][8][9][10] that the energies of the core electrone of the invariable atom A depend on X. This seeming paradox was analyzed in detail [1,6,11] in the literature on the X-ray electron spectroscopy and can be considered on the qualitative level by an example of the molecule AX 4 .…”

“…Abundant data [1,3,4,[6][7][8][9]11] show that the experimental E values are directly proportional to the calculated values of the charge Q.…”