scholarly journals A systematic study of the valence electronic structure of cyclo(Gly-Phe), cyclo(Trp-Tyr) and cyclo(Trp-Trp) dipeptides in gas phase

2021 ◽  
Author(s):  
Elena Molteni ◽  
Giuseppe Mattioli ◽  
Paola Alippi ◽  
Lorenzo Avaldi ◽  
Paola Bolognesi ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Gas Phase ◽  
Systematic Study ◽  
Energy Levels ◽  
Electronic Energy ◽  
Photoelectron Spectra ◽  
Electronic Energy Levels ◽  
Valence Electronic Structure

The electronic energy levels of cyclo(Glycine-Phenylalanine), cyclo(Tryptophan-Tyrosine) and cyclo(Tryptophan-Tryptophan) cyclic Glycine-Phenylalanine, Tryptophan-Tyrosine and Tryptophan-Tryptophan dipeptides are investigated with a joint experimental and theoretical ap- proach. Experimentally, valence photoelectron spectra in...

ON THE ELECTRONIC STRUCTURE OF C60

1993 ◽  
Vol 07 (22) ◽  
pp. 3877-3897 ◽  
Author(s):  
STUART SAMUEL
Keyword(s):  
Electronic Structure ◽  
Energy Levels ◽  
Electronic Energy ◽  
Experimental Results ◽  
Clear Picture ◽  
Lattice Methods ◽  
Coupling Case ◽  
Electronic Energy Levels

We determine the electronic energy levels of C60 using a combination of theoretical and experimental results. The hopping Hamiltonian for the truncated icosahedron is solved analytically for the unequal coupling case using group lattice methods. Then, an analysis of previously preformed experiments on electronic structure is undertaken. When these approaches are combined, a fairly clear picture of the location of the electronic levels emerges.

A Discussion on photoelectron spectroscopy - Molecular photoelectron spectroscopy

1970 ◽  
Vol 268 (1184) ◽  
pp. 7-31 ◽  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Energy Levels ◽  
Lone Pair ◽  
Electronic Energy ◽  
Photoelectron Spectra ◽  
Factors Affecting ◽  
Related Series ◽  
The Difference ◽  
Electronic Energy Levels ◽  
Vertical Ionization Energies

The principal features of helium 584 A photoelectron spectra of molecular vapours are outlined. Factors affecting the number of bands observed and their relation to the number of occupied electronic energy levels are discussed. The effect of the molecular translational velocity on the fundamental line widths attainable is considered and is shown to be significant though generally small compared with the much more common line broadening arising from ionic decomposition. Sharp lines are often to be associated with the presence of classical lone pairs but exceptions are noted. Structural effects in the lone pair ionization of chloro- and bromo-compounds are indicated. Some evidence is given for a correlation between the change in vibrational frequency produced upon ionization and the difference between adiabatic and vertical ionization energies. The use of such a correlation in the analysis of vibrational fine structure is exemplified by considering the examples of methylfluoride, 1,1-difluoroethylene, sulphur hexafluoride, ketene and pyrazine. A comparison between the p.e. spectra of butadiene, acrolein and glyoxal is used to indicate the utility of the method in creating energy level diagrams for related series of compounds.

scholarly journals Substitution Effects on Electronic Structure of Thiophene

1985 ◽  
Vol 40 (9) ◽  
pp. 1214-1218 ◽  
Author(s):  
Miroslav Bajić ◽  
Krešimir Humski ◽  
Leo Klasinc ◽  
Branko Ruščić
Keyword(s):  
Electronic Structure ◽  
Energy Levels ◽  
Electronic Energy ◽  
Substitution Effects ◽  
Electronic Energy Levels

The He (I) photoelectron (PE) spectra of the following methoxy (-MeO) and nitro (-NO2) thiophenes: 2-MeO, 3-MeO, 2,5-di-MeO, 2-NO2, 3-NO2, 2,4 -di-NO2 and 2,5 -di-NO2 have been recorded and their electronic structure is discussed in terms of inductive and mesomeric effects of substituent on the electronic energy levels of thiophene.

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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