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.

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.

A Discussion on photoelectron spectroscopy - Orderings of π and σ ionization potentials in carbocyclic and heterocyclic aromatic compounds

1970 ◽  
Vol 268 (1184) ◽  
pp. 131-140 ◽  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Aromatic Compounds ◽  
Lone Pair ◽  
Ionization Potentials ◽  
Photoelectron Spectra ◽  
Light Sources ◽  
Orbital Energies ◽  
Substituted Pyridines ◽  
Nitrogen Lone Pair ◽  
Electron Correlation Effects

Data on calculated orbital energies and experimentally measured ionization potentials of carbocyclic and heterocyclic aromatic compounds are compared and contrasted. The ordering or orbital energies and ionization potentials do not always seem to parallel one another, probably owing to either electron correlation effects, or to deviations from Koopman’s theorem. The effects on photoelectron spectra of using different light sources and analysers are discussed in relation to their bearing on the orbital orderings of aromatic compounds. The high resolution He 584 A. photoelectron spectrum of pyridine is shown to be open to two interpretations regarding the ordering of the ionization potentials of the π orbitals and the ‘nitrogen lone pair’ (n). One of the interpretations involves the three lowest pyridine ionization potentials being π (9.2 eV), π L (9.5 eV) and n (10.5 eV) whilst the other has the first three ionization potentials being the order π , n, π . The photoelectron spectra of substituted pyridines and diazines are discussed in the light of the two possible explanations for the pyridine spectrum.

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.

scholarly journals The absorption spectra of hexatriene and divinyl acetylene in the vacuum ultra-violet

1946 ◽  
Vol 185 (1001) ◽  
pp. 182-191 ◽  
Keyword(s):  
Double Bond ◽  
Ionization Potential ◽  
Absorption Spectra ◽  
Wave Length ◽  
Ultra Violet ◽  
Ionization Potentials ◽  
A Value ◽  
Integral Graphs ◽  
First Ionization Potential ◽  
Vacuum Ultra Violet

The absorption spectra of hexatriene and divinyl acetylene have been investigated in the region 2700-1200 A. In both molecules the longest wave-length regions of absorption are the strongest and these are interpreted as N → V 1 intravalence shell transitions. The spectra appear to be consistent with a value of about 8·2 V for the first ionization potential of hexatriene. Calculations based oh certain features of the spectra give reasonable values for the double-bond resonance integral. Graphs are given which enable the first regions of absorption and the ionization potentials of the higher polyenes to be predicted.

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.

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]

II. Empirical relations involving force constants and ionization potentials

1951 ◽  
Vol 207 (1088) ◽  
pp. 22-30 ◽  
Keyword(s):  
Ionization Potential ◽  
Force Constant ◽  
Force Constants ◽  
Ionization Potentials ◽  
Fixed Element ◽  
Empirical Relations ◽  
First Ionization Potential ◽  
Diatomic Hydride

The following empirical relations are found. The force constant ( k e ) of a diatomic hydride is roughly proportional to the square of the first ionization potential of the element forming the hydride. For a fixed element A and for B = F , Cl, B r or I, the plot of k e ( A — B ) versus I ( B ) is linear. The slope of this line (

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