He(I) and He(II) photoelectron spectra of iron tetracarbonyl-olefin complexes

The He(I) and He(II) photoelectron spectra of a series of iron tetracarbonyl—olefin complexes (olefin = acrolein, crotonaldehyde, methyl acrylate, acrylic acid, dimethyl maleate and some dihalogenated ethylenes) are reported. Assignments are proposed, based on differences in intensity between the He(I) and He(II) spectra, in comparison with related compounds and the results of extended CNDO calculations. The electronic structure of the coordinated olefins is discussed.     

He(I) and He(II) photoelectron spectra of some substituted ethylenes

The He(I) and He(II) photoelectron spectra of acrolein, acrylic acid, methyl acrylate, vinyl acetate, acrylamide and some of their methyl-substituted analogues are reported. Detailed assignments are proposed, mainly based on differences in intensity between the He(I) and He(II) spectra, on sum rule considerations and on the results of modified CNDO/S calculations.The assignment criteria are critically evaluated.     

The He(I) photoelectron spectra of amine N-oxides

The He(I) photoelectron spectrum of β-hydroxyethyldimethylamine N-oxide shows the degenerate pair of N-oxide ionic states to be shifted by 0.49 eV to higher ionization potential, relative to the non-hydrogen bonded system. The two bands remain nearly degenerate. The ionization of the hydroxy lone pair is shifted by > 0.6 eV to lower ionization potential. INDO calculations for the corresponding ionic configurations of a model system (NH₃O + H₂O) are compared with the experimental observations.     

He(I) and He(II) photoelectron spectra of glycine and related molecules

Photoelectron spectra obtained by He(I) and He(II) excitation of glycine, sarcosine and glycine methyl ester are presented. The p-type bands in the He(I) spectrum of glycine are interpreted in terms of localized molecular orbitals; the C 2s bands are identified in the He(II) spectrum. He(I) spectra of some N-acetylamino acids and of a variety of α-and ω-substituted amino acids are also reported.     

The He(I) photoelectron spectra of BrF and IF

The vacuum ultraviolet photoelectron spectra of BrF (X¹Σ⁺) and IF (X¹ Σ⁺) have been recorded and interpreted with the aid of both MS — Xα — SCF calculations and ab initio calculations. For both BrF and IF the first band is split by spin—orbit coupling into two components corresponding to ionization to the X²Π$\text{3}\text{2}$ Phytochemistry and X²Π$\text{1}\text{2}$ ionic states. Estimates of re, ?we and De for these states have been made.     

On the He(I) and Ne(I) photoelectron spectra of OCS

The He(I) (58.43 nm) and Ne(I) (73.59–74.37 nm) photoelectron spectra of carbonyl sulphide have been reinvestigated at an improved resolution and a high signal-to-noise ratio; deconvolution of the data was carried out to aid interpretation of the spectra. Improved values are deduced for the vibrational wavenumbers and the ionization energies. The spin—orbit components of the Ã²Π II level are well resolved and a value of 135 cm^?1 (17 ± 5 meV) is proposed for the splitting. Perturbations in the relative intensities are observed in the Ne(I) spectrum; they suggest that the autoionizing Rydberg state located around 73.7 nm is excited by the 73.59 nm Ne(I) line and contributes to populate, with different probabilities, the ionic levels of lower energy, and particularly the X?²Π state.     

The angular-distribution He(I)/Ne(I) photoelectron spectra of cyclopropane

The angular-distribution photoelectron spectrum of cyclopropane, studied with both He(I) and Ne(I) radiations, indicates negligible change in the asymm     

He(I) photoelectron spectroscopy of anions in adiponitrile solution

He(I) photoelectron spectra are reported of solutions of salts in adiponitrile in which peaks characteristic of the anions are visible; the vertical ionisation energies of these peaks are 6.91 and 7.85 (I^?), 7.6 (Br^?), 8.1 (Cl^?), 7.0 (CNS^?), 8.1 and 6.8 (NO₂^?), and 7.6eV (SO₄^2?). The salts examined were tetra-n-butyl ammonium (NO₂^?, I^?, Br^?, Cl^?, CNS^?, SO₄^2?), N-methylpyridinium I^?, trimethylphenylammonium I^?, choline I^?, methyltrioctylammonium I^? and methyltriphenylphosphonium Br^?. The relationship between these spectra and the charge transfer to solvent spectra of the anions is discussed.     

HE(I) Photoelectron spectra of 1,2-ethanediol in the liquid and gas phases

Nine bands in the He(I) gas-phase photoelectron spectrum of 1,2-ethanediol are assigned by means of ab initio calculation and by comparison with the sp     

He(II) photoelectron spectra of esters

Intensities of X-ray photoelectron transitions from the As 3d level are theoretically analysed taking into account many-electron interactions. The latter interactions profoundly affect the relative intensities of the transitions as well as binding energies. Implications for the surface structure of GaAs are then discussed and in particular we show that As atoms having the same chemical environment are spread over distances into the surface comparable to the interatomic spacing. This supports a recently proposed layer model for the untreated surface of GaAs.     

He(I) and He(II) photoelectron spectra of some organo-mercury compounds with carbon π-systems

The UV photoelectron spectra of a series of aromatic mercury derivatives {(C₆H₅)₂ Hg, (pCH₃C₆H₄)₂Hg, C₆H₅HgCl, pCH₃C₆H₄HgCl} and of a series of alkynyl mercury derivatives {(CH₃C)₂Hg, ((CCH₃)₃CCC)₂Hg, (ClCC)₂Hg} are reported and discussed. Particular attention is devoted to possible interactions between mercury orbitals and π systems of the ligands. In this respect differences are observed between the two series: in the alkynyl derivatives ligand-field effects are evident on the 5d mercury orbitals, whilst they are not observable in the aromatic compounds.     

He (Iα) photoelectron spectra of some higher aromatic perfluoro compounds

He(Iα) excited photoelectron spectra, the inferred ionisation energies, and their assignment, are presented for perfluoro-benzene, -naphthalene, -anthracene, -phenanthrene, -pyrene and -acenaphthylene.     

The He(I) and He(II) photoelectron spectra of bis (2,4,6-tri-t-butylphenyl)-diphosphene

Photoelectron spectra of the title compound have been obtained using various ionising radiations. The bands up to ～10 eV have been assigned with the aid of molecular-orbital calculations.