Reversal in the sequence of the two highest occupied molecular orbitals in the series pyrazine, 2,6-dimethylpyrazine, and tetramethylpyrazine

1974 ◽  
pp. 767 ◽  
Author(s):  
Peter Bischof ◽  
Rolf Gleiter ◽  
Peter Hofmann
Keyword(s):  
Molecular Orbitals ◽  
Highest Occupied Molecular Orbitals

scholarly journals Molecular Structure Modulated Trap Distribution and Carrier Migration in Fluorinated Epoxy Resin

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 3071 ◽  
Author(s):  
Jin Li ◽  
Yufan Wang ◽  
Zhaoyu Ran ◽  
Hang Yao ◽  
Boxue Du ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Surface Charge ◽  
Epoxy Resin ◽  
Mobility Model ◽  
Molecular Orbitals ◽  
Chemical Calculation ◽  
Dissipation Process ◽  
Highest Occupied Molecular Orbitals ◽  
Lowest Unoccupied Molecular Orbitals ◽  
Positively Charged

Surface charge accumulation on epoxy insulators is one of the most serious problems threatening the operation safety of the direct current gas-insulated transmission line (GIL), and can be efficiently inhibited by the surface modification technology. This paper investigated the mechanisms of fluorination modulated surface charge behaviors of epoxy resin through quantum chemical calculation (QCC) analysis of the molecular structure. The results show that after fluorination, the surface charge dissipation process of the epoxy sample is accelerated by the introduced shallow trap sites, which is further clarified by the carrier mobility model. The electron distribution probability of the highest occupied molecular orbitals (HOMO) under positive charging and the lowest unoccupied molecular orbitals (LUMO) under negative charging shows distinctive patterns. It is illustrated that electrons are likely to aggregate locally around benzenes for the positively charged molecular structure, while electrons tend to distribute all along the epoxy chain under negatively charging. The calculated results verify that fluorination can modulate surface charge behaviors of epoxy resin through redesigning its molecular structure, trap distribution and charging patterns.

Electron momentum spectroscopy of the highest occupied molecular orbitals of chlorobromomethane

2006 ◽  
Vol 1 (4) ◽  
pp. 424-427
Author(s):  
Xue-feng Yang ◽  
Fang Wu ◽  
Xu Shan ◽  
Mi Yan ◽  
Ke-dong Wang ◽  
...  
Keyword(s):  
Molecular Orbitals ◽  
Electron Momentum ◽  
Electron Momentum Spectroscopy ◽  
Highest Occupied Molecular Orbitals

Radical cation salt based on organic donor with close-lying highest occupied molecular orbitals

1991 ◽  
Vol 42 (3) ◽  
pp. 2301-2304 ◽  
Author(s):  
T. Bjørnholm ◽  
K. Bechgaard ◽  
P. Sommer-Larsen ◽  
G. Rindorf ◽  
N. Thorup
Keyword(s):  
Radical Cation ◽  
Molecular Orbitals ◽  
Radical Cation Salt ◽  
Highest Occupied Molecular Orbitals

Observational studies of imperfect carbon cage structures of C 60 by high-resolution scanning tunnelling microscopy

1994 ◽  
Vol 444 (1921) ◽  
pp. 325-332 ◽  
Keyword(s):  
High Resolution ◽  
Molecular Orbitals ◽  
Scanning Tunnelling Microscopy ◽  
Carbon Cage ◽  
Scanning Tunnelling ◽  
Tunnelling Microscopy ◽  
Dynamics Simulations ◽  
First Time ◽  
Highest Occupied Molecular Orbitals ◽  
Lowest Unoccupied Molecular Orbitals

Anomalies in the morphology of the carbon cage of C 60 clusters have been investigated with atomic level resolution using high-resolution scanning tunnelling microscopy. The imperfect carbon cages have been resolved in the finest detail, which, for the first time, provide a remarkable confirmation of a variety of theoretical defect structures recently predicted by molecular dynamics simulations. The observed tunnelling spectra are consistent with the theoretical contention that the gap between the highest occupied molecular orbitals (HOMO) and the lowest unoccupied molecular orbitals (LUMO) for the clusters is decreased with the presence of defects.

A Photoelectron Investigation of the Peroxide Bond

1975 ◽  
Vol 53 (22) ◽  
pp. 3439-3447 ◽  
Author(s):  
R. S. Brown
Keyword(s):  
Dihedral Angle ◽  
Ground State ◽  
Vibrational Frequencies ◽  
Molecular Orbitals ◽  
Photoelectron Spectra ◽  
Raman Spectroscopic ◽  
Orbital Interactions ◽  
Highest Occupied Molecular Orbitals ◽  
Peroxide Bond

The photoelectron spectra of several peroxides and their interpretation is presented. The effects of substituents is separated from vicinal orbital interactions using as a guideline the effect of similar substitution on the ether analogues. It is found that by comparison of Raman spectroscopic frequencies of the peroxide ground state, and vibrational frequencies for the ion (via pes), that the HOMO of peroxides is antibonding with respect to the O—O linkage. Additionally, the dependence of the splitting of the two highest occupied molecular orbitals on dihedral angle is verified by the pe spectra of several well-defined cyclic peroxides. Finally, the pe spectrum of tetramethyl-1,2-dioxacyclobutane (tetramethyl dioxetane) is presented indicating that it is not unlike other cyclic peroxides.

Nature of the highest occupied molecular orbitals oftrans- andcis-bicyclo[4.1.0]hept-3-enes

1995 ◽  
Vol 8 (3) ◽  
pp. 149-158
Author(s):  
Paul G. Gassman ◽  
Kata Mlinari?-Majerski ◽  
Branka Kova? ◽  
Han Chen ◽  
David A. Dixon
Keyword(s):  
Molecular Orbitals ◽  
Highest Occupied Molecular Orbitals

Reversal in the sequence of two highest occupied molecular orbitals in the series thiophen, selenophen, and tellurophen

1973 ◽  
Vol 0 (15) ◽  
pp. 541-542 ◽  
Author(s):  
Werner Schäfer ◽  
Armin Schweig ◽  
Salo Gronowitz ◽  
Aldo Taticchi ◽  
Francesco Fringuelli
Keyword(s):  
Molecular Orbitals ◽  
Highest Occupied Molecular Orbitals

scholarly journals A calculational and ultraviolet photoelectron spectroscopic study of distorted amides

1998 ◽  
Vol 76 (6) ◽  
pp. 672-677 ◽  
Author(s):  
N H Werstiuk ◽  
H M Muchall ◽  
C D Roy ◽  
J Ma ◽  
R S Brown
Keyword(s):  
Photoelectron Spectroscopy ◽  
Molecular Orbitals ◽  
Ultraviolet Photoelectron Spectroscopy ◽  
Excellent Correlation ◽  
Model Compounds ◽  
Ionization Energies ◽  
Highest Occupied Molecular Orbitals ◽  
Equilibrium Geometries ◽  
Good Agreement

Distorted amides 3,4-dihydro-2-oxo-1,4-ethanoquinoline (1a), 3,4-dihydro-2-oxo-1,4-propanoquinoline (1b), 3,3,4,5-tetrahydro-2-oxo-1,5-ethanobenzazepine (1c), and 3,3,4,5-tetrahydro-2-oxo-1,5-propanobenzazepine (1d) and the model compounds 2,N-dimethyl-acetanilide (2a), 2,N,N-trimethylaniline (3), and benzoquinuclidine (4) have been studied calculationally and with He(I) ultraviolet photoelectron spectroscopy. We find good agreement between experimentally obtained ionization energies for 1b, 1c, 1d, 2a, 3, and 4 and values calculated with HAM/3 using the equilibrium geometries obtained at the HF/6-31G** level of theory. An excellent correlation between experimental ionization energies and orbital energies from Becke3LYP/6-31+G* calculations led to the characterization of the highest occupied molecular orbitals for these compounds and for 1a, whose photoelectron spectrum could not be obtained due to its reactivity in the solid state.Key words: distorted amides, He(I) photoelectron spectroscopy, Becke3LYP, molecular orbitals.

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