Excitation Energy of 3B1 State of H2O Calculated from Generalized Oscillator Strengths

1975 ◽  
Vol 53 (19) ◽  
pp. 1825-1831 ◽  
Author(s):  
Kirby N. Klump ◽  
Edwin N. Lassettre
Keyword(s):  
Excitation Energy ◽  
Quantum Chemical Calculations ◽  
Upper Bound ◽  
Quantum Chemical ◽  
Approximate Formula ◽  
Oscillator Strengths ◽  
Initial Electron ◽  
Generalized Oscillator ◽  
Good Agreement

Generalized oscillator strengths have been determined for the 7.4 e V excitation in H2O at initial electron kinetic energies from 300 to 600 eV and squared momentum changes (of the colliding electron) to 4.5 a.u. These data are employed, in an approximate formula developed by Lassettre and Dillon, to calculate the excitation energy of the lowest 3B1 state of H2O. The value obtained, 7.0 eV, is in good agreement with accurate quantum chemical calculations and with experiment. The estimated uncertainty, based on errors found for CO and He, is 0.1 eV. This is a plausible estimate, not an upper bound.

The correlations and quantum chemical interpretations of some molecular properties of several p-phenylenediamines and related compounds

1987 ◽  
Vol 52 (4) ◽  
pp. 819-829 ◽  
Author(s):  
Günter Grampp ◽  
Peter Pluschke
Keyword(s):  
Exchange Rates ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Activation Energies ◽  
Molecular Properties ◽  
Ionization Potentials ◽  
Related Compounds ◽  
Good Agreement

Quantum chemical calculations of various p-phenylenediamines and related compounds are correlated with different molecular properties, such as electrochemical E1/2-values, ionization potentials, pK-values, UV-VIS spectra, the activation energies of the homogeneous electron self-exchange rates, and the synproportionation constants. All correlations are in good agreement with the predictions of simple HMO-theory.

scholarly journals Specific Impulse and Absolute Chemical Hardness

2020 ◽  
Author(s):  
George Santos Marinho ◽  
Robson de Farias
Keyword(s):  
Quantum Chemical Calculations ◽  
Reference Values ◽  
Quantum Chemical ◽  
Specific Impulse ◽  
Chemical Hardness ◽  
The Absolute ◽  
Good Agreement

<p>The present work is dedicated to show that there are relationships between the absolute chemical hardness (η) of monopropellants and their specific impulse (I<sub>s</sub>). A total of sixteen monopropellants have been modelled and the absolute hardness obtained by quantum chemical calculations. The following equation was obtained: I<sub>s</sub> = 17.562 η + 125.551, providing specific impulse results in very good agreement with reference values. </p> <p> </p>

scholarly journals A Robust Supramolecular Heterosynthon Assembled by a Hydrogen Bond and a Chalcogen Bond

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1309
Author(s):  
Shaobin Miao ◽  
Yunfan Zhang ◽  
Linjie Shan ◽  
Mingyuan Xu ◽  
Jian-Ge Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Crystal Structures ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Noncovalent Interactions ◽  
Isophthalic Acid ◽  
Stacking Interactions ◽  
Chalcogen Bond ◽  
Good Agreement

The 1:1 and 2:1 cocrystals of isophthalic acid and 2,1,3-benzoselenadiazole have been successfully synthesized and resolved; the noncovalent interactions in the crystal structures have been studied in detail by quantum chemical calculations. In both of the crystal structures, isophthalic acid and 2,1,3-benzoselenadiazole are bound together by a cyclic supramolecular heterosynthon assembled by an O–H···N hydrogen bond and a N–Se···O chalcogen bond. The crystal structures of the 1:1 and 2:1 cocrystals of isophthalic acid and 2,1,3-benzoselenadiazole and the crystal structure of pure isophthalic acid are very similar, which indicates that the [COOH]···[Se−N] cyclic heterosynthon can be an effective alternative to the strong [COOH]2 cyclic homosynthon. The quantum theory of atoms in molecules further recognizes the existence of the hydrogen bond and chalcogen bond. The results of quantum chemical calculations show that the strengths of the π···π stacking interactions in the 1:1 cocrystals of isophthalic acid and 2,1,3-benzoselenadiazole are almost the same as those in the 2:1 cocrystals of isophthalic acid and 2,1,3-benzoselenadiazole, and the strengths of the [COOH]···[Se−N] cyclic heterosynthons (about 9.00 kcal/mol) are less than the strengths of the much stronger [COOH]2 cyclic homosynthons (14.00 kcal/mol). These calculated results are in good agreement with those experimentally observed, demonstrating that, although not as strong as the [COOH]2 cyclic homosynthon, the [COOH]···[Se−N] cyclic heterosynthon can also play a key role in the crystal growth and design.

scholarly journals Specific Impulse and Absolute Chemical Hardness

2020 ◽  
Author(s):  
George Santos Marinho ◽  
Robson de Farias
Keyword(s):  
Quantum Chemical Calculations ◽  
Reference Values ◽  
Quantum Chemical ◽  
Specific Impulse ◽  
Chemical Hardness ◽  
The Absolute ◽  
Good Agreement

<p>The present work is dedicated to show that there are relationships between the absolute chemical hardness (η) of monopropellants and their specific impulse (I<sub>s</sub>). A total of sixteen monopropellants have been modelled and the absolute hardness obtained by quantum chemical calculations. The following equation was obtained: I<sub>s</sub> = 17.562 η + 125.551, providing specific impulse results in very good agreement with reference values. </p> <p> </p>

Oscillator Strength Measurements in the Vacuum-Ultraviolet by the Emission Method

1988 ◽  
Vol 102 ◽  
pp. 353-356
Author(s):  
C. Goldbach ◽  
G. Nollez
Keyword(s):  
Oscillator Strength ◽  
Vacuum Ultraviolet ◽  
Oscillator Strengths ◽  
Emission Method ◽  
Absolute Scale ◽  
Good Agreement

AbstractThe principles and the realization of an experiment devoted to oscillator strength measurements in the vacuum-ultraviolet by the emission method are briefly presented. The results obtained for the strong multiplets of neutral nitrogen and carbon in the 1200-2000 Å range yield an absolute scale of oscillator strengths in good agreement with the most recent calculations.

Discovery of a Difluoroglycine Synthesis Method through Quantum Chemical Calculations

2020 ◽  
Author(s):  
Tsuyoshi Mita ◽  
Yu Harabuchi ◽  
Satoshi Maeda
Keyword(s):  
Quantum Chemical Calculations ◽  
Experimental Verification ◽  
Quantum Chemical ◽  
Synthesis Method ◽  
Target Product ◽  
Systematic Exploration ◽  
Hands On ◽  
Retrosynthetic Analysis ◽  
Synthetic Routes ◽  
Verification Process

The systematic exploration of synthetic pathways to afford a desired product through quantum chemical calculations remains a considerable challenge. In 2013, Maeda et al. introduced ‘quantum chemistry aided retrosynthetic analysis’ (QCaRA), which uses quantum chemical calculations to search systematically for decomposition paths of the target product and propose a synthesis method. However, until now, no new reactions suggested by QCaRA have been reported to lead to experimental discoveries. Using a difluoroglycine derivative as a target, this study investigated the ability of QCaRA to suggest various synthetic paths to the target without relying on previous data or the knowledge and experience of chemists. Furthermore, experimental verification of the seemingly most promising path led to the discovery of a synthesis method for the difluoroglycine derivative. The extent of the hands-on expertise of chemists required during the verification process was also evaluated. These insights are expected to advance the applicability of QCaRA to the discovery of viable experimental synthetic routes.

Discovery of a Difluoroglycine Synthesis Method through Quantum Chemical Calculations

2020 ◽  
Author(s):  
Tsuyoshi Mita ◽  
Yu Harabuchi ◽  
Satoshi Maeda
Keyword(s):  
Quantum Chemical Calculations ◽  
Experimental Verification ◽  
Quantum Chemical ◽  
Synthesis Method ◽  
Target Product ◽  
Systematic Exploration ◽  
Hands On ◽  
Retrosynthetic Analysis ◽  
Synthetic Routes ◽  
Verification Process

The systematic exploration of synthetic pathways to afford a desired product through quantum chemical calculations remains a considerable challenge. In 2013, Maeda et al. introduced ‘quantum chemistry aided retrosynthetic analysis’ (QCaRA), which uses quantum chemical calculations to search systematically for decomposition paths of the target product and propose a synthesis method. However, until now, no new reactions suggested by QCaRA have been reported to lead to experimental discoveries. Using a difluoroglycine derivative as a target, this study investigated the ability of QCaRA to suggest various synthetic paths to the target without relying on previous data or the knowledge and experience of chemists. Furthermore, experimental verification of the seemingly most promising path led to the discovery of a synthesis method for the difluoroglycine derivative. The extent of the hands-on expertise of chemists required during the verification process was also evaluated. These insights are expected to advance the applicability of QCaRA to the discovery of viable experimental synthetic routes.

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