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.

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 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 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 first ionization potential of the formyl radical, HCO(X2A′), studied using photoelectron spectroscopy

1980 ◽  
Vol 39 (3) ◽  
pp. 629-636 ◽  
Author(s):  
J.M. Dyke ◽  
N.B.H. Jonathan ◽  
A. Morris ◽  
M.J. Winter
Keyword(s):  
Ionization Potential ◽  
Photoelectron Spectroscopy ◽  
Formyl Radical ◽  
First Ionization Potential

The first ionization potential of ethyl radical by photoelectron spectroscopy

1977 ◽  
Vol 48 (3) ◽  
pp. 457-460 ◽  
Author(s):  
F.A. Houle ◽  
J.L. Beauchamp
Keyword(s):  
Ionization Potential ◽  
Photoelectron Spectroscopy ◽  
Ethyl Radical ◽  
First Ionization Potential

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.

Improved first ionization potential of the dimethylsilaethylene molecule obtained with high-temperature photoelectron spectroscopy

1982 ◽  
Vol 86 (15) ◽  
pp. 2913-2916 ◽  
Author(s):  
J. M. Dyke ◽  
G. D. Josland ◽  
R. A. Lewis ◽  
A. Morris
Keyword(s):  
High Temperature ◽  
Ionization Potential ◽  
Photoelectron Spectroscopy ◽  
First Ionization Potential

A study of the first ionization potential of the CrO(X5Π) molecule with high-temperature photoelectron spectroscopy

1983 ◽  
Vol 79 (7) ◽  
pp. 1083-1088 ◽  
Author(s):  
John M. Dyke ◽  
Brian W. J. Gravenor ◽  
Robert A. Lewis ◽  
Alan Morris
Keyword(s):  
High Temperature ◽  
Ionization Potential ◽  
Photoelectron Spectroscopy ◽  
First Ionization Potential
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