Photoelectron Spectra and Molecular Properties, XLVIII Carbonates and Thiocarbonates

1975 ◽  
Vol 30 (11-12) ◽  
pp. 862-874 ◽  
Author(s):  
K. Wittel ◽  
E. E. Astrup ◽  
H. Bock ◽  
G. Graeffe ◽  
H. Juslén
Keyword(s):  
Ionization Potential ◽  
Substituent Effects ◽  
Lone Pair ◽  
Emission Spectra ◽  
Low Energy ◽  
Photoelectron Spectra ◽  
Energy Bands ◽  
Open Chain ◽  
First Ionization Potential ◽  
Cndo Calculations

Photoelectron (PE) spectra of ethylene and vinylene carbonates and thiocarbonates as well as of methylene trithiocarbonate and some open-chain derivatives are reported.The low energy bands, well separated in the unsaturated compounds, are assigned to lone pair and π type ionizations. The assignment is based on comparison of PE spectra, modified CNDO calculations, and sulfur Κβ emission spectra. The pronounced substituent effects due to which the first ionization potential varies from 8.4 eV to 11.1 eV are discussed.

Photoelectron spectroscopic studies of the Propyl- and Allyl-substituted amines

1977 ◽  
Vol 30 (12) ◽  
pp. 2571 ◽  
Author(s):  
JB Peel ◽  
GD Willett
Keyword(s):  
Ionization Potential ◽  
Density Of States ◽  
Lone Pair ◽  
Spectroscopic Studies ◽  
Photoelectron Spectra ◽  
Sum Rule ◽  
Nitrogen Lone Pair ◽  
Lone Pair Electrons ◽  
First Ionization Potential

The HeI (21.22 eV) photoelectron spectra of the mono-, di- and tri- propyl- and allyl-substituted amines are reported up to 21 eV. The assignments are based on SPINDO calculations, on the comparison with other related molecules, a density of states analysis and a sum rule treatment. The first ionization potential band in each of the spectra is assigned to the nitrogen lone-pair electrons and for the allylamines the second band is assigned to the ethylenic π-bond electrons.

Electronic Levels of Methyl Amines by Photoelectron Spectroscopy and an i.n.d.o. Calculation

1971 ◽  
Vol 49 (7) ◽  
pp. 1135-1136 ◽  
Author(s):  
A. B. Cornford ◽  
D. C. Frost ◽  
F. G. Herring ◽  
C. A. McDowell
Keyword(s):  
Binding Energy ◽  
Ionization Potential ◽  
Photoelectron Spectroscopy ◽  
Lone Pair ◽  
Ionization Potentials ◽  
The One ◽  
First Ionization Potential

The ionization potentials of the methyl amines down to 20 eV binding energy, have been determined by photoelectron spectroscopy, and are compared with those predicted by i.n.d.o.-l.c.a.o.-s.c.f. theory. The first ionization potential for each compound refers to the removal of an electron from the lone pair, and is shown to be the one most affected by the inclusion of one center repulsion integrals in the i.n.d.o. calculations.

Photoelectron spectroscopy of hydrogen-bonded systems: spectra of monomers, dimers and mixed complexes of carboxylic acids

1972 ◽  
Vol 331 (1585) ◽  
pp. 249-261 ◽  
Keyword(s):  
Hydrogen Bonding ◽  
Ionization Potential ◽  
Carboxylic Acids ◽  
Photoelectron Spectroscopy ◽  
Free Acid ◽  
Photoelectron Spectra ◽  
Target Chamber ◽  
Donor Group ◽  
Mixed Complexes ◽  
First Ionization Potential

By cooling the target chamber of a photoelectron spectrometer, the photoelectron spectra of dimers and mixed complexes of carboxylic acids have been obtained. By comparison of the spectra with each other and with those of the monomers, it has been possible to assign several bands to ionization from specific molecular orbitals. Hydrogen-bonding changes most ionization potentials of the monomers but not by more than about 0.5 eV. In particular, the ionization potential of an electron from a non-bonding orbital on the proton donor group is decreased and that from a non-bonding orbital on the electron donor group is increased. This is consistent with most theories of hydrogen bonding. In the mixed complexes it makes the first ionization potential higher than that of the free acids, dimers, however, are complicated by the initial degeneracy of their orbitals and this results in their first ionization potential being lower than for the free acid. There is also some evidence that the hydrogen bonds in a complex between different acids are of unequal strength.

The photoelectron spectra of the propylbenzenes

1978 ◽  
Vol 31 (3) ◽  
pp. 483 ◽  
Author(s):  
F Carnovale ◽  
E Nagy-Felsobuki ◽  
JB Peel
Keyword(s):  
Energy Range ◽  
Ionization Potential ◽  
Ionization Energy ◽  
Photoelectron Spectra ◽  
Molecule Model ◽  
First Ionization Potential ◽  
Isopropyl Benzene

The HeI photoelectron spectra of propyl- and isopropyl-benzene have been measured and compared. The two isomers have the same first ionization potential, but show variations in the higher ionization energy range. Comparison with the benzene and propane spectra, aided by the results of SPINDO calculations, indicates that the propylbenzene spectra can be interpreted according to a composite-molecule model.

The electronic structure of cyclopentadienylindium

1982 ◽  
Vol 60 (6) ◽  
pp. 699-702 ◽  
Author(s):  
C. S. Lin ◽  
Dennis G. Tuck
Keyword(s):  
Electronic Structure ◽  
Dipole Moment ◽  
Related Species ◽  
Lone Pair ◽  
Photoelectron Spectra ◽  
Covalent Interaction ◽  
Orbital Energies ◽  
Calculated Dipole Moment ◽  
Dominant Feature ◽  
Cndo Calculations

CNDO calculations have been carried out for the molecule InC5H5 of C5υ symmetry. Overlap populations were calculated and compared with those for related species. The bonding between In and the organic moiety can be described as essentially a covalent interaction involving mainly indium 5s and 5p orbitals with ring pπ orbitals. A lone pair on indium is a dominant feature of the structure, and is largely responsible for a (calculated) dipole moment of 4.75 D. The calculated orbital energies are compared with experimental photoelectron spectra.

scholarly journals Ionization potentials of nitriles — Photoelectron spectra of succinonitrile and glutaronitrile

2006 ◽  
Vol 84 (9) ◽  
pp. 1124-1131 ◽  
Author(s):  
Heidi M Muchall ◽  
Nick H Werstiuk
Keyword(s):  
Energy Region ◽  
Photoelectron Spectrum ◽  
Lone Pair ◽  
Low Energy ◽  
Ionization Potentials ◽  
Photoelectron Spectra ◽  
Proton Affinities ◽  
Nitrogen Lone Pair ◽  
D Model ◽  
Highest Occupied Molecular Orbitals

The He(I) photoelectron spectra of succinonitrile (1) and glutaronitrile (2), both with extensive overlap of ionization bands in the low-energy region, are reported. To assign ionizations, we studied the conformational behaviour and resulting ionization energy dependence of 1 and 2 computationally with the B3LYP/6-31+G(d) model chemistry based on the fact that it reliably reproduces the ionization potentials of eleven mono- and di-nitriles, both saturated and unsaturated. The correlation of proton affinities with observed ionization potentials of 1, 2, and malononitrile establishes the orbital sequence of four C≡N π orbitals followed by two nitrogen lone pair orbitals as the highest occupied molecular orbitals for all three compounds.Key words: photoelectron spectrum, ionization potential, conformational dependence, nitrile, DFT.

Article

1998 ◽  
Vol 76 (2) ◽  
pp. 221-227
Author(s):  
Heidi M Muchall ◽  
Nick H Werstiuk ◽  
Biswajit Choudhury
Keyword(s):  
Ionization Potential ◽  
Photoelectron Spectroscopy ◽  
Quantum Chemical ◽  
Lone Pair ◽  
Basis Sets ◽  
Eigenvalues And Eigenvectors ◽  
Adiabatic Ionization Potential ◽  
Experimental Values ◽  
Ab Initio Hf ◽  
First Ionization Potential

Photoelectron (PE) spectra of two stable carbenes 7 and 8 have been recorded and the spectra have been interpreted with the aid of eigenvalues and eigenvectors taken from Becke3LYP calculations. For the carbene series 6-8, the lone pair on the carbene carbon atom is the HOMO. The first adiabatic ionization potential (IP) of eight electronically quite different carbenes has been calculated using semiempirical PM3 and ab initio HF, Becke3LYP, and Becke3PW91 methods (3-21G(*) and 6-31+G* basis sets) as well as the CBS-4 model. For the first vertical IP, the HAM/3, Becke3LYP, and Becke3PW91 methods have been employed. CBS-4 and DFT calculations show excellent agreement with experimental values. Considering both accuracy and speed, the method of choice for the prediction of first ionization potentials of carbenes seems to be Becke3LYP/6-31+G*//Becke3LYP/3-21G(*).Key words: carbenes, electronic structure, first ionization potential, photoelectron spectroscopy, quantum chemical calculations.

Spectres photoélectroniques de cyclohexène-2 ones-1 diversement substituées en position 3. Correlations avec la réactivité

1982 ◽  
Vol 60 (10) ◽  
pp. 1163-1172 ◽  
Author(s):  
Geneviève Pfister-Guillouzo ◽  
Serge Geribaldi ◽  
Jean-François Gal
Keyword(s):  
Linear Relationship ◽  
Ionization Potential ◽  
Methylene Chloride ◽  
Substituent Effects ◽  
Lone Pair ◽  
Carbonyl Oxygen ◽  
Ionization Potentials ◽  
Aromatic Ketones ◽  
Different Types ◽  
Oxygen Lone Pair

We have recorded the photoelectronic spectra of 32 differently 3-substituted 2-cyclohexen-1-ones as well as those of 10 para-substituted acetophenones. Assignment of most of the cyclohexenone bands is made and the substituent effects on the π-electron ionization potentials and of the oxygen lone pair are discussed. The linear relationship between the ionization potential of the carbonyl oxygen lone pair and σp-type constants as well as those between the ionization potentials and the enthalpies of complexation (ΔH0) of the ketones with BF3 in methylene chloride allows us to propose that the direct conjugative interaction between the substituents and the carbonyl group is weak in the free ketone but becomes very strong in the complexed or protonated state. The existence of two distinct relationships (ΔH0 = f(PI n0) for 3-substituted cyclohexenones and the aromatic ketones indicates that this type of expression cannot be used for the comparison of the Lewis basicities of different types of ketones; on the contrary, these expressions do allow for the comparison of the relative basicities of the same type. [Journal Translation]

The far ultra-violet absorption spectra of the hydrides and deuterides of sulphur, selenium and tellurium and of the methyl derivatives of hydrogen sulphide

1950 ◽  
Vol 201 (1067) ◽  
pp. 600-609 ◽  
Keyword(s):  
Ionization Potential ◽  
Absorption Spectra ◽  
Ground State ◽  
Lone Pair ◽  
Ultra Violet ◽  
General Nature ◽  
Rydberg Series ◽  
Group Vi ◽  
Methyl Derivatives ◽  
First Ionization Potential

The absorption spectra in the vacuum ultra-violet of the hydrides and deuterides of sulphur, selenium and tellurium, and methyl mercaptan and dimethyl sulphide are described. Well-developed Rydberg series leading to the following ionization potentials have been found: H 2 S, 10.47V; MeSH, 9.44V; H 2 Se, 9.88V; H 2 Te, 9.14V. In the case of one series for H 2 Se fifteen members of the series were observed. The spectra of the deuterides are almost identical with those of the hydrides, showing that virtually every band in the spectra is due to a separate electronic transition. This and the general nature of the rotational fine structure show the transitions concerned to be those of an electron from a non-bonding ground-state orbital, i.e. from the p lone-pair ground-state orbital. The nature of the upper orbitals of the various series is also interpreted and shown to provide explanations of certain peculiarities of the observations. The quantity I(X) — J(H 2 X), where X is a group VI element, or I ( Y ) — I ( HY), where Y is a group VII element, is shown to be positive and comparatively large when X or Y lies in the first period of the periodic table, but to change sign and to remain almost constant at a small negative value as one passes to elements in later periods. A plot of I (H 2 X)against the first ionization potential of the corresponding inert gas is linear. Extrapolation enables the first ionization potential of H 2 Po to be predicted at 8.6V. A similar plot for the halogen acids, if assumed linear, yields a predicted first ionization potential for HF of 17.0±0.7V.

High-resolution silicon Kβ X-ray spectra and crystal structure

1989 ◽  
Vol 53 (370) ◽  
pp. 239-244 ◽  
Author(s):  
J. Purton ◽  
D. S. Urch
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Molecular Orbital ◽  
Local Structure ◽  
Emission Spectra ◽  
High Energy ◽  
Low Energy ◽  
Photoelectron Spectra ◽  
Peak Width ◽  
X Ray

AbstractHigh-resolution X-ray emission spectra (XES) are presented for minerals with a variety of structures. The participation of the Si 3p orbitals in bonding is influenced by the local structure around the silicon atom. In orthosilicates the distortion of the SiO44--tetrahedron influences both peak-width and the intensity of the high-energy shoulder of the Si-Kβ spectrum. In minerals containing Si-O-Si bonds there is mixing of the Si 3s and 3p orbitals giving rise to a peak on the low-energy side of the main Si-Kβ peak. When combined with X-ray photoelectron spectra (XPS), a complete molecular orbital picture of bonding can be established.

Sign in / Sign up

Export Citation Format

Share Document