Separation of 1La Excitation Energies of Conjugated Hydrocarbons into Orbital Energy Difference and Two‐Electron Term Contributions

1967 ◽  
Vol 46 (10) ◽  
pp. 3889-3894 ◽  
Author(s):  
J. Michl ◽  
Ralph S. Becker
Keyword(s):  
Energy Difference ◽  
Orbital Energy ◽  
Excitation Energies ◽  
Conjugated Hydrocarbons ◽  
Electron Term

scholarly journals Linear Correlation Models for the Redox Potential of Organic Molecules in Aqueous Solutions

2019 ◽  
Author(s):  
Jessica C. Ortiz-Rodríguez ◽  
Juan A. Santana ◽  
Dalvin Méndez-Hernández
Keyword(s):  
Aqueous Solutions ◽  
Solvent Effects ◽  
Linear Correlation ◽  
Correlation Coefficients ◽  
Energy Difference ◽  
Orbital Energy ◽  
Difference Approximation ◽  
Redox Potentials ◽  
Correlation Models ◽  
Solvent Model

<p>In this study we use the molecular orbital energy approximation (MOEA) and the energy difference approximation (EDA) to build linear correlation models for the redox potentials of 53 organic compounds in aqueous solutions. The molecules evaluated include nitroxides, phenols and amines. Both the MOEA and EDA methods yield similar correlation models, however the MOEA method is less computationally expensive. Correlation coefficients (R2) below 0.3 and mean absolute errors above 0.25 V were found for correlation models built without solvent effects. When explicit water molecules and a continuum solvent model are added to the calculations, correlation coefficients close to 0.8 are reached and mean absolute errors below 0.18 V are obtained. The incorporation of solvent effects is necessary for good correlation models, particularly for redox processes of charged molecules in aqueous solutions. A comparison of the correlation models from different methodologies is provided.<br></p>

Relationship between orbital energy gaps and excitation energies for long-chain systems

2016 ◽  
Vol 37 (16) ◽  
pp. 1451-1462 ◽  
Author(s):  
Takao Tsuneda ◽  
Raman K. Singh ◽  
Ayako Nakata
Keyword(s):  
Orbital Energy ◽  
Excitation Energies ◽  
Energy Gaps ◽  
Long Chain

scholarly journals Linear Correlation Models for the Redox Potential of Organic Molecules in Aqueous Solutions

2019 ◽  
Author(s):  
Jessica C. Ortiz-Rodríguez ◽  
Juan A. Santana ◽  
Dalvin Méndez-Hernández
Keyword(s):  
Aqueous Solutions ◽  
Solvent Effects ◽  
Linear Correlation ◽  
Correlation Coefficients ◽  
Energy Difference ◽  
Orbital Energy ◽  
Difference Approximation ◽  
Redox Potentials ◽  
Correlation Models ◽  
Solvent Model

<p>In this study we use the molecular orbital energy approximation (MOEA) and the energy difference approximation (EDA) to build linear correlation models for the redox potentials of 53 organic compounds in aqueous solutions. The molecules evaluated include nitroxides, phenols and amines. Both the MOEA and EDA methods yield similar correlation models, however the MOEA method is less computationally expensive. Correlation coefficients (R2) below 0.3 and mean absolute errors above 0.25 V were found for correlation models built without solvent effects. When explicit water molecules and a continuum solvent model are added to the calculations, correlation coefficients close to 0.8 are reached and mean absolute errors below 0.18 V are obtained. The incorporation of solvent effects is necessary for good correlation models, particularly for redox processes of charged molecules in aqueous solutions. A comparison of the correlation models from different methodologies is provided.<br></p>

peri-Acenoacene Molecules: Tuning of the Singlet and Triplet Excitation Energies by Modifying their Radical Character

2021 ◽  
Author(s):  
Alicia Omist ◽  
Gaetano Ricci ◽  
Amel Derradji ◽  
Ángel J. José Pérez-Jiménez ◽  
Emilio San Fabián ◽  
...  
Keyword(s):  
Light Emission ◽  
Energy Difference ◽  
Delayed Fluorescence ◽  
Excitation Energies ◽  
Thermally Activated Delayed Fluorescence ◽  
Triplet Excitation ◽  
Thermally Activated ◽  
Radical Character ◽  
Triplet Excitons

The energy difference between singlet and triplet excitons, or ΔEST, is a key magnitude for novel light-emission mechanisms (i.e., TADF or Thermally Activated Delayed Fluorescence) or other photoactivated processes. We...

Fermi-Amaldi model for exchange-correlation: atomic excitation energies from orbital energy differences

2005 ◽  
Vol 103 (15-16) ◽  
pp. 2061-2072 ◽  
Author(s):  
Paul W. Ayers * ◽  
Robert C. Morrison ◽  
Robert G. Parr
Keyword(s):  
Orbital Energy ◽  
Excitation Energies ◽  
Exchange Correlation ◽  
Atomic Excitation

scholarly journals Monte Carlo Approach to Total π-Electron Energy of Conjugated Hydrocarbons

1985 ◽  
Vol 40 (10) ◽  
pp. 1059-1061
Author(s):  
I. Gutman ◽  
M. Rašković
Keyword(s):  
Monte Carlo ◽  
Distribution Function ◽  
Molecular Orbital ◽  
Electron Energy ◽  
Energy Levels ◽  
Random Variables ◽  
Orbital Energy ◽  
Monte Carlo Approach ◽  
Type Formula ◽  
Conjugated Hydrocarbons

Approximating the π-electron molecular orbital energy levels by uniformly distributed random variables, a McClelland-type formula for the total π-electron energy is obtained. Conditions are determined under which a given distribution function will result in a formula of McClelland type.

Spatially Resolved Photoelectron Spectroscopy: Recent Progress and Future Plans

1990 ◽  
Vol 48 (2) ◽  
pp. 388-389
Author(s):  
A. M. Bradshaw
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Reactivity ◽  
Target Material ◽  
Orbital Energy ◽  
Light Sources ◽  
Analytical Technique ◽  
Hartree Fock ◽  
Spatially Resolved ◽  
Koopmans Theorem ◽  
Surface Analytical Technique

X-ray photoelectron spectroscopy (XPS or ESCA) was not developed by Siegbahn and co-workers as a surface analytical technique, but rather as a general probe of electronic structure and chemical reactivity. The method is based on the phenomenon of photoionisation: The absorption of monochromatic radiation in the target material (free atoms, molecules, solids or liquids) causes electrons to be injected into the vacuum continuum. Pseudo-monochromatic laboratory light sources (e.g. AlKα) have mostly been used hitherto for this excitation; in recent years synchrotron radiation has become increasingly important. A kinetic energy analysis of the so-called photoelectrons gives rise to a spectrum which consists of a series of lines corresponding to each discrete core and valence level of the system. The measured binding energy, EB, given by EB = hv−EK, where EK is the kineticenergy relative to the vacuum level, may be equated with the orbital energy derived from a Hartree-Fock SCF calculation of the system under consideration (Koopmans theorem).

Energy Levels and Electromagnetic Transition of 90-94mo Nuclei Using Ibm-1

2020 ◽  
pp. 149-152
Keyword(s):  
Experimental Data ◽  
Transition Probability ◽  
Energy Levels ◽  
Dynamical Symmetry ◽  
Interacting Boson Model ◽  
Excitation Energies ◽  
Electromagnetic Transition ◽  
Boson Model ◽  
Energy States ◽  
Good Agreement

The energy states for the J , b , ɤ bands and electromagnetic transitions B (E2) values for even – even molybdenum 90 – 94 Mo nuclei are calculated in the present work of "the interacting boson model (IBM-1)" . The parameters of the equation of IBM-1 Hamiltonian are determined which yield the best excellent suit the experimental energy states . The positive parity of energy states are obtained by using IBS1. for program for even 90 – 94 Mo isotopes with bosons number 5 , 4 and 5 respectively. The" reduced transition probability B(E2)" of these neuclei are calculated and compared with the experimental data . The ratio of the excitation energies of the 41+ to 21+ states ( R4/2) are also calculated . The calculated and experimental (R4/2) values showed that the 90 – 94 Mo nuclei have the vibrational dynamical symmetry U(5). Good agreement was found from comparison between the calculated energy states and electric quadruple probabilities B(E2) transition of the 90–94Mo isotopes with the experimental data .

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