Assignment of the valence molecular orbitals of (cyclopentadienyl)trimethylplatinum and (cyclooctadiene)dimethylplatinum using variable-energy photoelectron spectra

1990 ◽  
Vol 29 (24) ◽  
pp. 4956-4960 ◽  
Author(s):  
D. S. Yang ◽  
G. M. Bancroft ◽  
R. J. Puddephatt ◽  
K. H. Tan ◽  
J. N. Cutler ◽  
...  
1989 ◽  
Vol 28 (1) ◽  
pp. 1-2 ◽  
Author(s):  
Dong Sheng Yang ◽  
G. Michael Bancroft ◽  
John D. Bozek ◽  
R. J. Puddephatt ◽  
John S. Tse

The photoelectron spectra of diborane, hexadeuterodiborane, borazine and B -trifluoroborazine are presented, and adiabatic and vertical ionization potentials have been measured. The vibrational fine structure observed on some of the diborane bands is shown to be consistent with the forms of the molecular orbitals calculated by rigorous s.c.f. methods. The vertical i.p. of diborane are in better accord with a calculation which predicts a boron-boron bond in addition to the hydrogen bridge than with the calculations which indicate no direct boron-boron interaction. In borazine it is shown that the uppermost orbital is of π type rather than the σ type predicted by calculations, and that the extent of the π bonding, as measured by the energy separation of the π-type orbitals, is about 85 % of that in benzene. The effect of fluorination of borazine, as in benzene, is to stabilize the σ orbitals more than the π orbitals.


Photoelectron spectra are reported for the hydrides of group v and vi elements. Vibrational structure has been observed in bands associated with all but the inner-most valence orbitals. It has been used to obtain changes in bond angles or bond distances which result from the ionization of successive molecular orbitals. Ionization from the inner (la 1 ) orbitals of the hydrides has been observed using He II 304 Å+ radiation. From these data vertical ionization potentials have been derived for all the valence orbitals of the hydrides XH, XH 2 , XH 3 and XH 4 for which the corresponding united atoms are Ne, A, Kr and Xe. Graphs of these values are used to show the effects of inner shells on the valence orbitals.


Photoelectron spectra of chloro-, fluoro- and chlorofluoroethylenes have been measured. Ionization potentials in the range 6 to 21 eV have been determined, and vibrational structure associated with many of the electronic transitions has been interpreted in terms of vibrations of the ion and correlated with those of the parent molecule. The various ionization potentials have been associated with specific orbitals such as the C=C π orbital, and molecular orbitals derived from the p atomic orbitals of halogens. Variations in these ionization potentials have been discussed in relation to inductive and conjugative effects of the halogen substituents. Some observed differences between the spectra of the chloro- and fluoroethylenes have been considered in relation to possible mechanisms of the changes in bond length consequent upon ionization.


1987 ◽  
Vol 65 (4) ◽  
pp. 683-686 ◽  
Author(s):  
Dieter Klapstein ◽  
Robert T. O'Brien

The He(I) photoelectron spectra of propenal and the propenoyl halides, CH2=CHCOX, X = H, F, Cl, Br, were measured and interpreted with the aid of semi-empirical MO calculations, comparison with results for structurally related species, and a sum-rule for the out-of-plane orbital energies. Information concerning the identities and relative energies of the higher occupied molecular orbitals of the neutral molecules could be deduced from the spectra.


2015 ◽  
Vol 30 (2) ◽  
pp. 83-98 ◽  
Author(s):  
Yury Teterin ◽  
Konstantin Maslakov ◽  
Mikhail Ryzhkov ◽  
Anton Teterin ◽  
Kirill Ivanov ◽  
...  

Quantitative analysis was done of the X-ray photoelectron spectra structure in the binding energy range of 0 eV to ~35 eV for americium dioxide (AmO2) valence electrons. The binding energies and structure of the core electronic shells (~35 eV-1250 eV), as well as the relativistic discrete variation calculation results for the Am63O216 and AmO8 (D4h) cluster reflecting Am close environment in AmO2 were taken into account. The experimental data show that the many-body effects and the multiplet splitting contribute to the spectral structure much less than the effects of formation of the outer (0-~15 eV binding energy) and the inner (~15 eV-~35 eV binding energy) valence molecular orbitals. The filled Am 5f electronic states were shown to form in the AmO2 valence band. The Am 6p electrons participate in formation of both the inner and the outer valence molecular orbitals (bands). The filled Am 6p3/2 and the O 2s electronic shells were found to make the largest contributions to the formation of the inner valence molecular orbitals. Contributions of electrons from different molecular orbitals to the chemical bond in the AmO8 cluster were evaluated. Composition and sequence order of molecular orbitals in the binding energy range 0-~35 eV in AmO2 were established. The experimental and theoretical data allowed a quantitative scheme of molecular orbitals for AmO2, which is fundamental for both understanding the chemical bond nature in americium dioxide and the interpretation of other X-ray spectra of AmO2.


1992 ◽  
Vol 31 (25) ◽  
pp. 5162-5163 ◽  
Author(s):  
Xiaorong Li ◽  
G. M. Bancroft ◽  
R. J. Puddephatt ◽  
Y. F. Hu ◽  
Z. Liu ◽  
...  

2015 ◽  
Vol 17 (16) ◽  
pp. 10656-10667 ◽  
Author(s):  
Branka Kovač ◽  
Ivan Ljubić ◽  
Antti Kivimäki ◽  
Marcello Coreno ◽  
Igor Novak

UV and X-ray photoelectron spectra of three N-heterocyclic carbenes under synchrotron radiation reveal details of their electronic structure and are used as a benchmark to test computational methods for treating core ionizations in systems with unusual electronic structures.


1975 ◽  
Vol 53 (22) ◽  
pp. 3439-3447 ◽  
Author(s):  
R. S. Brown

The photoelectron spectra of several peroxides and their interpretation is presented. The effects of substituents is separated from vicinal orbital interactions using as a guideline the effect of similar substitution on the ether analogues. It is found that by comparison of Raman spectroscopic frequencies of the peroxide ground state, and vibrational frequencies for the ion (via pes), that the HOMO of peroxides is antibonding with respect to the O—O linkage. Additionally, the dependence of the splitting of the two highest occupied molecular orbitals on dihedral angle is verified by the pe spectra of several well-defined cyclic peroxides. Finally, the pe spectrum of tetramethyl-1,2-dioxacyclobutane (tetramethyl dioxetane) is presented indicating that it is not unlike other cyclic peroxides.


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