Characterization of Homonuclear Diatomic Ions by Semiempirical Morse Potential Energy Curves. 1. The Halogen Anions

1996 ◽  
Vol 100 (23) ◽  
pp. 9649-9657 ◽  
Author(s):  
J. G. Dojahn ◽  
E. C. M. Chen ◽  
W. E. Wentworth
Keyword(s):  
Potential Energy ◽  
Morse Potential ◽  
Potential Energy Curves

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.

Potential energy curves of low-lying states of HNO

1979 ◽  
Vol 66 (3) ◽  
pp. 523-526 ◽  
Author(s):  
Okio Nomura ◽  
Suehiro Iwata
Keyword(s):  
Potential Energy ◽  
Potential Energy Curves
Sign in / Sign up

Export Citation Format

Share Document