scholarly journals Квантовая модель диполь-индуцированный диполь и влияние инертного окружения на интенсивность ИК поглощения

2019 ◽  
Vol 127 (8) ◽  
pp. 212
Author(s):  
А.П. Коузов ◽  
Н.И. Егорова ◽  
А.Н. Добротворская
Keyword(s):  
Absorption Bands ◽  
Rigorous Results ◽  
Reaction Field ◽  
Dipole Interactions ◽  
Cryogenic Solutions ◽  
Induced Dipole ◽  
Vibrational Bands ◽  
Semi Empirical ◽  
Numerical Estimations

Based on the diagrammatic techniques, a theory of the imaginary part of the isotropic polarizability induced by the dipole-dipole interactions between isotropically polarizable particles is elaborated. A classification of single infrared resonances corresponding to cases of the allowed and interaction-induced absorption bands is proposed. The Dipole-Induced-Dipole (DID) diagrammatic terms causing the allowed intensity variations via the reaction-field effect are analytically summed up. The thus-derived rigorous results are in conflict with the semi-empirical Onsager-Bottcher model. For the simplest reference systems (cryogenic solutions of HCl and HBr), our numerical estimations demonstrate the reaction-field contributions to observed intensity variations of vibrational bands to be weak and to become even weaker with a growth of the solvent particle dimensions that suggests the inadequacy of the DID and Onsager-Bottcher models to experimental data.

scholarly journals Optical absorption of LiNaGe4O9:Mn crystal

2021 ◽  
Vol 29 (1) ◽  
pp. 69-72
Author(s):  
A. Yu. Osetsky ◽  
T. V. Panchenko ◽  
M. D. Volnianskii ◽  
M. P. Trubitsyn
Keyword(s):  
Field Theory ◽  
Optical Absorption ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Optical Absorption Spectra ◽  
Crystal Field Theory ◽  
Absorption Bands ◽  
Additional Absorption ◽  
Impurity Ions ◽  
Semi Empirical

The paper reports the results of optical absorption spectra studying in LiNaGe4O9 crystal doped with Mn. It is shown that Mn impurity causes the appearance of the additional absorption bands. The intensities of these bands change in different ways in the range of the ferroelectric phase transition. Semi-empirical version of the crystal field theory is used to discuss localization and charge state of Mn impurity ions in the LiNaGe4O9 structure.

scholarly journals Theoretical Prediction on the New Types of Noble Gas Containing Anions OBONgO− and OCNNgO− (Ng=He, Ar, Kr and Xe)

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5839
Author(s):  
Cheng-Cheng Tsai ◽  
Yu-Wei Lu ◽  
Wei-Ping Hu
Keyword(s):  
Density Functional Theory ◽  
Electron Density Distribution ◽  
Density Functional ◽  
Noble Gas ◽  
Structure Calculation ◽  
Molecular Structures ◽  
Fluoride Ion ◽  
Functional Theory ◽  
Dipole Interactions ◽  
Induced Dipole

The fluorine-less noble gas containing anions OBONgO− and OCNNgO− have been studied by correlated electronic structure calculation and density functional theory. The obtained energetics indicates that for Ng=Kr and Xe, these anions should be kinetically stable at low temperature. The molecular structures and electron density distribution suggests that these anions are stabilized by ion-induced dipole interactions with charges concentrated on the electronegative OBO and OCN groups. The current study shows that in addition to the fluoride ion, polyatomic groups with strong electronic affinities can also form stable noble gas containing anions of the type Y−…NgO.

SOLVENT EFFECTS ON THE PROTON RESONANCE SPECTRA OF THE DICHLORO- AND DIBROMO-ETHYLENES: REACTION FIELD EFFECTS IN ALIPHATIC SOLVENTS AND SPECIFIC INTERACTIONS IN AROMATIC SOLVENTS

1963 ◽  
Vol 41 (12) ◽  
pp. 3034-3041 ◽  
Author(s):  
F. Hruska ◽  
E. Bock ◽  
T. Schaefer
Keyword(s):  
Field Effect ◽  
Dielectric Constants ◽  
Specific Interactions ◽  
Proton Resonance ◽  
Water Solutions ◽  
Reaction Field ◽  
Aromatic Solvents ◽  
Triple Bonds ◽  
Induced Dipole ◽  
Cis And Trans

The proton resonance shifts relative to internal cyclohexane and tetramethylsilane of cis and trans dichloro- and dibromo-ethylenes were measured in dioxane–water solutions, aliphatic solvents, and aromatic solvents. The dielectric constants of the dioxane–water solutions could be smoothly varied between 2 and 10 and, by taking Δ = cis–trans shifts as containing only the dipolar reaction field effect, the data for these solutions were treated as a test of the Buckingham reaction field equation. Linear plots were obtained and reasonable values of the coefficients of the E term confirmed the usefulness of this equation. An equation based on a nonspherical cavity was also used. It was also shown that quadrupolar reaction fields affected the proton shifts. Sizeable deviations from the dioxane–water standards were found for halogenated aliphatic solvents and those containing double or triple bonds. These deviations are interpreted in terms of the shape of the solute molecules and dispersion and anisotropic interactions. The much larger deviations found for aromatic solvents are harder to rationalize but specific interactions were found for both cis and trans forms, indicating an inadequacy in a simple dipole-induced dipole model.

THE CRYSTAL SPECTRUM OF PERYLENE

1961 ◽  
Vol 39 (3) ◽  
pp. 451-458 ◽  
Author(s):  
Robin M. Hochstrasser
Keyword(s):  
Absorption Spectrum ◽  
Electronic Absorption ◽  
Weak Coupling ◽  
Room Temperature ◽  
Excited Level ◽  
Vibrational Structure ◽  
Factor Group ◽  
Electronic Band ◽  
Dipole Interactions ◽  
Induced Dipole

The electronic absorption spectrum of crystalline perylene has been examined in the spectral region 3000–4700 Å. The lowest energy electronic state of perylene has a large oscillator strength and the crystal spectrum deviates considerably from that calculated from a weak coupling (Davydov) model.The sublimation flakes were examined at room temperature and at the temperature of boiling nitrogen. The lowest energy crystal state was polarized along the crystallographic a-axis (Bu) and the factor group splitting of lowest vibrational envelope of the electronic band was 800 cm−1. The whole spectrum was more intense along the a- than along the b-axis of the crystal. These results are consistent with the notion that the crystal spectrum is derived from dipole-induced dipole interactions between molecular B2u levels of perylene and neighboring unexcited molecules. This assignment of the lowest excited level of perylene is in agreement with theory.The molecular vibrational structure is severely altered in the crystal and the observed crystal shift is much smaller than that predicted by the Davydov theory.

scholarly journals Bimolecular Reactions of Trapped Ions. VI. Ion–Molecule Reactions Involving CH5+ and C2H5+

1973 ◽  
Vol 51 (10) ◽  
pp. 1645-1654 ◽  
Author(s):  
A. S. Blair ◽  
A. G. Harrison
Keyword(s):  
Proton Transfer ◽  
Trapped Ions ◽  
Rate Coefficients ◽  
Polar Molecules ◽  
Large Role ◽  
Bimolecular Reactions ◽  
Trapped Ion ◽  
Ion Molecule Reactions ◽  
Dipole Interactions ◽  
Induced Dipole

The ion–molecule reactions in mixtures of methane with the polar molecules dimethyl-d6 ether, ethylene-d4 oxide, acetaldehyde-d4, acetone, and acetonitrile have been studied using the trapped-ion technique. The CH5+ and C2H5+ ions produced by ion–molecule reactions in methane react rapidly (predominantly by proton transfer) with the polar molecules; the rate coefficients range from 1.98 × 10−9 cm3 molecule−1 s−1 (C2H5+ + C2D4O) to 5.26 × 10−9 cm3 molecule−1 s−1 (CH5+ + (CH3)2CO). The rate coefficients are much larger than those predicted from ion – induced dipole interactions only indicating that ion–dipole interactions play a large role in the collision process.Rate coefficients for reaction of CH3+ and CH4+ with the polar molecules also have been measured. Most of these also are larger than predicted from ion – induced dipole interactions indicating in this case as well substantial effects due to ion–dipole interactions.

Charge-transfer complexes of purines and pyrimidines

1968 ◽  
Vol 21 (2) ◽  
pp. 419 ◽  
Author(s):  
A Fulton ◽  
LE Lyons
Keyword(s):  
Charge Transfer ◽  
Field Method ◽  
Charge Transfer Complexes ◽  
Absorption Bands ◽  
Consistent Field ◽  
Highest Occupied Molecular Orbital ◽  
Self Consistent Field ◽  
Semi Empirical ◽  
Purines And Pyrimidines ◽  
Good Agreement

The spectra of 20 purines and pyrimidines with chloranil, bromanil, and p-benzoquinone in dimethyl sulphoxide were studied. Most of the systems exhibited absorption bands which were concluded to be charge transfer in nature. The ionization energies of the molecules, derived from the positions of the bands, correlated well with the highest occupied molecular orbital energies calculated using the simple H�ckel method and were also in good agreement with ionization energy values calculated by a semi-empirical self-consistent field method.

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