THE ELECTRONIC STATES OF LINEAR METHYLENE

1961 ◽  
Vol 39 (8) ◽  
pp. 1652-1656 ◽  
Author(s):  
G. W. King ◽  
G. L. Malli
Keyword(s):  
Ground State ◽  
Energy Levels ◽  
Electronic States ◽  
Electronic Energy ◽  
The State ◽  
Electronic Energy Levels ◽  
Combining States ◽  
Lcao Mo

The electronic energy levels of the linear methylene radical, with r(C—H) = 1.0295 Å, have been calculated by the LCAO/MO/CI procedure. The state of lowest energy has 3∑g− symmetry, and is accompanied by low-lying 1Δg and 1∑g+ states. Allowed intravalence shell transitions from the ground state (3Πu−3∑g−,−3∑u−−3∑g−) are too high in energy to account for the observed transition at 8.6 ev, indicating that the latter is of Rydberg type if it is between linear combining states.

THE ELECTRONIC STATES OF CIS- AND TRANS-ACETYLENE

1959 ◽  
Vol 37 (4) ◽  
pp. 700-707 ◽  
Author(s):  
H. Howard ◽  
G. W. King
Keyword(s):  
Ground State ◽  
Energy State ◽  
Energy Levels ◽  
Electronic States ◽  
Electronic Energy ◽  
Class A ◽  
Allowed Transition ◽  
Form Part ◽  
Electronic Energy Levels ◽  
Cis And Trans

The electronic energy levels of cis- and trans-bent planar centrosymmetric acetylene molecules, with [Formula: see text] and r cc = 1.383 Å, have been calculated by the LCAO/ASMO/CI procedure. The lowest energy state that can spectroscopically combine with the linear ground state is found to be of symmetry class Au belonging to the trans-bent molecule and to lie at 4.58 ev above the ground state. This compares favorably with the experimentally observed electronic transition of lowest energy which is of type (1Au−1∑g+) and at 5.24 ev. The lowest-energy allowed transition to a cis-bent state of these dimensions is at 9.39 ev, and hence this may not form part of the unanalyzed system of bands in the 2000–1500 Å region, as has been suggested. However, a transition to a trans-bent state of type (1Bu−1∑g+) is predicted to fall in this region. The energies of other electronic states are discussed in relation to the observed absorption systems of acetylene.

3d Transition Metals in II-VI Semiconductors

1989 ◽  
Vol 161 ◽  
Author(s):  
D. Heiman ◽  
M. Dahl ◽  
X. Wang ◽  
P.A. Wolff ◽  
P. Becla ◽  
...  
Keyword(s):  
Light Scattering ◽  
Transition Metals ◽  
Ground State ◽  
Energy Levels ◽  
Electronic Energy ◽  
Donor Level ◽  
Orbital Moment ◽  
Inelastic Light Scattering ◽  
Electronic Energy Levels ◽  
Van Vleck

ABSTRACTThe magnetic and electronic properties of some I-VI semiconductors with 3d transition metals other than Mn are presented. For example, the nonzero orbital moment in Fe2+ leads to more complex electronic energy levels than for Mnt ions. In (CdFe)Se, inelastic light scattering experiments demonstrate that the ground state is nonmagnetic (Van Vleck ion), and directly measures the energy spacing between the three lowest levels. For Sc2+ ions the donor level lies above the bottom of the conduction band in the Cd-based materials.

ELECTRONIC POTENTIAL SURFACES OF ACETYLENE IN LCAO/MO APPROXIMATION

1960 ◽  
Vol 38 (3) ◽  
pp. 365-372 ◽  
Author(s):  
G. W. King
Keyword(s):  
Nuclear Charge ◽  
Energy Levels ◽  
Electronic Energy ◽  
Potential Surfaces ◽  
Carbon Carbon Bond ◽  
Input Variables ◽  
Electronic Energy Levels ◽  
Electronic Transition Energies ◽  
Electronic Potential ◽  
Lcao Mo

A digital computer has been programmed to carry out 6-electron LCAO/ASMO calculations for linear and trans-bent acetylene, with the following input variables; coefficients of the LCAO/MOs, carbon–carbon bond length, and effective nuclear charge on the carbon atoms. The effect of varying these parameters upon the calculated electronic energy levels is discussed, and approximations to "best" MOs are obtained for various states of the molecule, leading to values of hybridization parameters for the carbon atoms. Certain assumptions enable the electronic energies to be related to the C—C—H bending angle; from this it is concluded the ground state is linear and the lowest Au excited state is bent, in accordance with experiment. Values are given for electronic transition energies and hydrogen-bending force constants.

scholarly journals The ultra-violet spectrum of magnesium hydride. 1.—The band at λ 2430

1929 ◽  
Vol 122 (790) ◽  
pp. 442-455 ◽  
Keyword(s):  
Fine Structure ◽  
General Structure ◽  
Energy Levels ◽  
Visible Region ◽  
Ultra Violet ◽  
Present Theory ◽  
Magnesium Hydride ◽  
Electronic Energy ◽  
Band Spectra ◽  
Electronic Energy Levels

The system of bands in the visible region of the emission spectrum of magnesium hydride is now well known. The bands with heads at λλ 5622, 5211, 4845 were first measured by Prof. A. Fowler, who arranged many of the strongest lines in empirical series for identification with absorption lines in the spectra of sun-spots. Later, Heurlinger rearranged these series in the now familiar form of P, Q and R branches, and considered them, with the OH group, as typical of doublet systems in his classification of the fine structure of bands. More recently, W. W. Watson and P. Rudnick have remeasured these bands, using the second order of a 21-foot concave grating, and have carried out a further investigation of the fine structure in the light of the present theory of band spectra. Their detection of an isotope effect of the right order of magnitude, considered with the general structure of the system, and the experimental work on the production of the spectrum, seems conclusive in assigning these bands to the diatomic molecule MgH. The ultra-violet spectrum of magnesium hydride is not so well known. The band at λ 2430 and the series of double lines in the region λ 2940 to λ 3100, which were recorded by Prof. Fowler in 1909 as accompanying the group of bands in the visible region, appear to have undergone no further investigation. In view of the important part played by hydride band spectra in the correlation of molecular and atomic electronic energy levels, it was thought that a study of these features might prove of interest in yielding further information on the energy states of the MgH molecule. The present paper deals with observations on the band at λ 2430; details of an investigation of the other features of the ultra-violet spectrum will be given in a later communication.

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