Semiempirical Characterization of Homonuclear Diatomic Ions:  5. The General Classification of Herschbach Ionic Morse Potential Energy Curves

2002 ◽  
Vol 106 (28) ◽  
pp. 6665-6669 ◽  
Author(s):  
Edward S. Chen ◽  
Edward C. M. Chen
Keyword(s):  
Potential Energy ◽  
Morse Potential ◽  
Potential Energy Curves ◽  
General Classification

scholarly journals Strength, character, and directionality of halogen bonds involving cationic halogen bond donors

2017 ◽  
Vol 203 ◽  
pp. 47-60 ◽  
Author(s):  
Kevin E. Riley ◽  
Khanh-An Tran
Keyword(s):  
Potential Energy ◽  
Halogen Bond ◽  
Model System ◽  
Potential Energy Curves ◽  
Chloride Salt ◽  
Halogen Bonds ◽  
Charged Species ◽  
Implicit Solvation Model ◽  
The Stability

Halogen bonds involving cationic halogen bond donors and anionic halogen bond acceptors have recently been recognized as being important in stabilizing the crystal structures of many salts. Theoretical characterization of these types of interactions, most importantly in terms of their directionality, has been limited. Here we generate high-quality symmetry adapted perturbation theory potential energy curves of a H3N–CC–Br+⋯Cl− model system in order to characterize halogen bonds involving charged species, in terms of contributions from electrostatics, exchange, induction, and dispersion, with special emphasis on analyzing contributions that are most responsible for the directionality of these interactions. It is found that, as in the case of neutral halogen bonds, exchange forces are important contributors to the directionality of charged halogen bonds, however, it is also found that induction effects, which contribute little to the stability and directionality of neutral halogen bonds, play a large role in the directionality of halogen bonds involving charged species. Potential energy curves based on the ωB97X-D/def2-TZVP/C-PCM method, which includes an implicit solvation model in order to mimic the effects of the crystal medium, are produced for both the H3N–CC–Br+⋯Cl− model system and for the 4-bromoanilinium⋯Cl− dimer, which is based on the real 4-bromoanilinium chloride salt, whose crystal structure has been determined experimentally. It is found that, within a crystal-like medium, charged halogen bond are significantly weaker than in the gas phase, having optimum interaction energies up to approximately −20 kcal mol−1.

A Modern Approach for the Identification of the Classical and Modified Generalized Morse Potential

2020 ◽  
Vol 10 (2) ◽  
pp. 142-151 ◽  
Author(s):  
Samuel A. Surulere ◽  
Micheal Y. Shatalov ◽  
Andrew C.P.G. Mkolesia ◽  
Igor Fedotov
Keyword(s):  
Parameter Estimation ◽  
Potential Energy ◽  
Least Squares ◽  
Morse Potential ◽  
Gold Atom ◽  
Initial Guess ◽  
Potential Energy Curves ◽  
Complex Conjugate ◽  
Modern Approach ◽  
Generalized Morse Potential

Introduction: This paper proposes an approach for parameter estimation of the Classical and Generalized Morse Potential functions. A new potential which is a modification of the Generalized Morse Potential was proposed as parameter estimates yielded complex conjugate roots using gold atom for simulation. Methods: Existing methods of parameter estimation requires the provision of initial guess values of which convergence to the optimal solution is not always guaranteed. This makes provision of initial guess values that guarantees convergence to the optimum solution more of an art than a science. The proposed objective least squares function method does not require the provision of initial guess values and it involves the minimization of two formulated objective functions using the differential numerical approach and least squares method. The built-in “Minimize” function of Mathematica® is also used to minimize the formulated objective function. Potential energy curves were constructed by fitting estimated parameter values to experimental data sets of the gold atom using values of the proposed approach and Mathematica® for performance evaluation. Errors of each constructed potential energy curves were simulated. Results: It was observed that the errors were very small for both the Classical and Modified Generalized Morse Potential. Conclusion: Hence the approximations of the proposed approach are very good.

FUNDAMENTAL NATURE AND CLASSIFICATION OF LABOR MIGRATION

2020 ◽  
Vol 1 (3) ◽  
pp. 14-23
Author(s):  
Tulkin Chulliev ◽  
Keyword(s):  
Labor Migration ◽  
General Classification ◽  
Fundamental Nature

The article explains the fundamental nature of migration by combining the definitions given by other scholars. The issue of labor migration is analyzed. One of the most important problems in contemporary migration processes - the problem of classification- is researched and a general classification is provided

scholarly journals Morphological and Ultrastructural Characterization of Hemocytes in an Insect Model, the Hematophagous Dipetalogaster maxima (Hemiptera: Reduviidae)

Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 640
Author(s):  
Natalia R. Moyetta ◽  
Fabián O. Ramos ◽  
Jimena Leyria ◽  
Lilián E. Canavoso ◽  
Leonardo L. Fruttero
Keyword(s):  
Cell Biology ◽  
Cell Types ◽  
Transmission Electron ◽  
Ultrastructural Characterization ◽  
Current Classification ◽  
Contrast Microscopy ◽  
First Time ◽  
Controversial Aspect

Hemocytes, the cells present in the hemolymph of insects and other invertebrates, perform several physiological functions, including innate immunity. The current classification of hemocyte types is based mostly on morphological features; however, divergences have emerged among specialists in triatomines, the insect vectors of Chagas’ disease (Hemiptera: Reduviidae). Here, we have combined technical approaches in order to characterize the hemocytes from fifth instar nymphs of the triatomine Dipetalogaster maxima. Moreover, in this work we describe, for the first time, the ultrastructural features of D. maxima hemocytes. Using phase contrast microscopy of fresh preparations, five hemocyte populations were identified and further characterized by immunofluorescence, flow cytometry and transmission electron microscopy. The plasmatocytes and the granulocytes were the most abundant cell types, although prohemocytes, adipohemocytes and oenocytes were also found. This work sheds light on a controversial aspect of triatomine cell biology and physiology setting the basis for future in-depth studies directed to address hemocyte classification using non-microscopy-based markers.

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