Solution Spectra and Oscillator Strengths of Electronic Transitions of Pyridine and Some Monosubstituted Derivatives

1954 ◽  
Vol 22 (6) ◽  
pp. 1077-1082 ◽  
Author(s):  
Harold P. Stephenson
Keyword(s):  
Oscillator Strengths ◽  
Electronic Transitions

THEORETICAL STUDIES ON THE ELECTRONIC SPECTRA OF SUBSTITUTED AROMATIC MOLECULES: PART II. SEMIEMPIRICAL SELF-CONSISTENT FIELD CALCULATIONS ON ANILINE

1964 ◽  
Vol 42 (1) ◽  
pp. 121-136 ◽  
Author(s):  
J. E. Bloor ◽  
P. N. Daykin ◽  
P. Boltwood
Keyword(s):  
Ionization Potential ◽  
Oscillator Strengths ◽  
Electronic Transitions ◽  
Aromatic Molecules ◽  
The Core ◽  
Consistent Field ◽  
Aniline Molecule ◽  
Self Consistent Field ◽  
Reasonable Choice ◽  
Experimental Values

The results of 14 calculations on the aniline molecule using different choices of parameters within the framework of the semiempirical SCFMO method have been carried out using an automatic Fortran 1A program written for an I.B.M. 1620 computer. It has been shown that the approximation of using the valence state ionization potential as a measure of the core integral of a heteroatomic substituent underestimates the amount of electron transfer between substituent AO and the benzene MO's. By adjusting this core integral empirically or by using a variable electronegativity MO approach it has been found possible to obtain, for the same set of parameters, agreement between experiment and theory for: the first two electronic transitions in the vapor state (4.23–4.38 ev and 5.22–5.41 ev), the change in ionization potential relative to benzene (AI = 1.54 ev), and the electron density para to the amino group (ρ4π = 1.059). It was not found possible to calculate values for the π-electron dipole moment and oscillator strengths which agreed, for any reasonable choice of parameters, with experimental values.

IR-Absorption Spectra of Impurities in 6H-SiC

1994 ◽  
Vol 339 ◽  
Author(s):  
F. Engelbrecht ◽  
R. Helbig
Keyword(s):  
Temperature Dependence ◽  
Excited States ◽  
Oscillator Strengths ◽  
Electronic Transitions ◽  
Ir Absorption ◽  
Orbit Splitting ◽  
Ir Absorption Spectra ◽  
Nitrogen Donor ◽  
Splitting Energy ◽  
Vibronic Transitions

ABSTRACTWe performed infrared absorption and reflectivity measurements on serverai 6H-SiC samples at variable temperatures between T=5K and T=300K. From the temperature dependence of the observed absorption lines we separated electronic from vibronic transitions. The electronic transitions are assumed to be due to transitions from the neutral nitrogen donor occupying the three different carbon lattice sites in 6H-SiC into excited states. We determined polarization and the oscillator strengths of these transitions. From the temperature dependence of the electronic transitions we determined the valley-orbit-splitting energy and we demonstrated the influence of compensation. For the different vibronic transitions we determined the Grüneisen constants.

scholarly journals Prediction of Molecular Electronic Transitions Using Random Forests

2020 ◽  
Author(s):  
Beomchang Kang ◽  
Chaok Seok ◽  
Juyong Lee
Keyword(s):  
Random Forest ◽  
Design Principle ◽  
Oscillator Strengths ◽  
Electronic Transitions ◽  
Quantum Yields ◽  
Excitation Energies ◽  
Structure And Dynamics ◽  
Feature Importance ◽  
Importance Analysis ◽  
Fluorescent Molecules

<div>Fluorescent molecules, fluorophores, play essential roles in bioimaging. Attachment</div><div>of fluorophores to proteins enables observation of the detailed structure and dynamics</div><div>of biological reactions occurring in the cell. Effective bioimaging requires fluorophores</div><div>with high quantum yields to detect weak signals. Besides, fluorophores with various</div><div>emission frequencies are necessary to extract richer information. An essential com-</div><div>putational component to discover novel functional molecules is to predict molecular</div><div>properties. Here, we present statistical machines that predict excitation energies and</div><div>associated oscillator strengths of a given molecule using a random forest algorithm. Ex-</div><div>citation energies and oscillator strengths are directly related to the emission spectrum</div><div>and the quantum yields of fluorophores, respectively. We discovered specific molecu-</div><div>lar substructures and fragments that determine the oscillator strengths of molecules</div><div>from the feature importance analysis of our random forest machine. This discovery is</div><div>expected to serve as a new design principle for novel fluorophores.</div>

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