scholarly journals The influence of dispersion slope to the higher-order dispersion coefficients for highly-nonlinear fibers

2017 ◽  
Author(s):  
N. Othman ◽  
N. S. M. Shah ◽  
K. G. Tay ◽  
H. Pakarzadeh ◽  
N. A. Cholan ◽  
...  
Keyword(s):  
Higher Order ◽  
Dispersion Coefficients ◽  
Dispersion Slope ◽  
Nonlinear Fibers ◽  
Highly Nonlinear ◽  
Higher Order Dispersion ◽  
Order Dispersion

Evaluating the London Dispersion Coefficients of Protein Force Fields Using the Exchange-Hole Dipole Moment Model

2018 ◽  
Author(s):  
Evan T. Walters ◽  
Mohamad Mohebifar ◽  
Erin R. Johnson ◽  
Christopher Rowley
Keyword(s):  
Dipole Moment ◽  
Force Fields ◽  
Higher Order ◽  
Side Chain ◽  
Dispersion Interactions ◽  
Dispersion Coefficients ◽  
Hydration Energies ◽  
London Dispersion ◽  
Higher Order Dispersion ◽  
Order Dispersion

<div>London dispersion is one of the fundamental intermolecular interactions involved in protein folding and dynamics. The popular CHARMM36, Amber ff14sb, and OPLS-</div><div>AA force fields represent these interactions through the C6 /r 6 term of the Lennard-Jones potential. The C6 parameters are assigned empirically, so these parameters are</div><div>not necessarily a realistic representation of the true dispersion interactions. In this work, dispersion coefficients of all three force fields were compared to corresponding</div><div>values from quantum-chemical calculations using the exchange-hole dipole moment (XDM) model. The force field values were found to be roughly 50% larger than the XDM values for protein backbone and side-chain models. The CHARMM36 and Amber OL15 force fields for nucleic acids were also found to exhibit this trend. To explore how these elevated dispersion coefficients affect predicted properties, the hydration energies of the side-chain models were calculated using the staged REMD-TI method of Deng and Roux for the CHARMM36, Amber ff14sb, and OPLS-AA force fields. Despite having large C 6 dispersion coefficients, these force fields predict side-chain hydration energies that are in generally good agreement with the experimental values, including for hydrocarbon residues where the dispersion component is the dominant attractive solute–solvent interaction. This suggests that these force fields predict the correct total strength of dispersion interactions, despite C6 coefficients that are considerably larger than XDM predicts. An analytical expression for the water–methane dispersion energy using XDM dispersion coefficients shows that that higher-order dispersion terms(i.e., C 8 and C 10 ) account for roughly 37.5% of the hydration energy of methane. This suggests that the C 6 dispersion coefficients used in contemporary force fields are</div><div>elevated to account for the neglected higher-order terms. Force fields that include higher-order dispersion interactions could resolve this issue.</div>

Calculation of higher order dispersion coefficients in photonic crystal fibers

2011 ◽  
Author(s):  
A. Martínez-Rios ◽  
Boaz Ilan ◽  
I. Torres-Gómez ◽  
D. Monzon-Hernandez ◽  
D. E. Ceballos-Herrera
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystal Fibers ◽  
Higher Order ◽  
Dispersion Coefficients ◽  
Crystal Fibers ◽  
Higher Order Dispersion ◽  
Order Dispersion

Evaluating the London Dispersion Coefficients of Protein Force Fields Using the Exchange-Hole Dipole Moment Model

2018 ◽  
Author(s):  
Evan T. Walters ◽  
Mohamad Mohebifar ◽  
Erin R. Johnson ◽  
Christopher Rowley
Keyword(s):  
Dipole Moment ◽  
Force Fields ◽  
Higher Order ◽  
Side Chain ◽  
Dispersion Interactions ◽  
Dispersion Coefficients ◽  
Hydration Energies ◽  
London Dispersion ◽  
Higher Order Dispersion ◽  
Order Dispersion

<div>London dispersion is one of the fundamental intermolecular interactions involved in protein folding and dynamics. The popular CHARMM36, Amber ff14sb, and OPLS-</div><div>AA force fields represent these interactions through the C6 /r 6 term of the Lennard-Jones potential. The C6 parameters are assigned empirically, so these parameters are</div><div>not necessarily a realistic representation of the true dispersion interactions. In this work, dispersion coefficients of all three force fields were compared to corresponding</div><div>values from quantum-chemical calculations using the exchange-hole dipole moment (XDM) model. The force field values were found to be roughly 50% larger than the XDM values for protein backbone and side-chain models. The CHARMM36 and Amber OL15 force fields for nucleic acids were also found to exhibit this trend. To explore how these elevated dispersion coefficients affect predicted properties, the hydration energies of the side-chain models were calculated using the staged REMD-TI method of Deng and Roux for the CHARMM36, Amber ff14sb, and OPLS-AA force fields. Despite having large C 6 dispersion coefficients, these force fields predict side-chain hydration energies that are in generally good agreement with the experimental values, including for hydrocarbon residues where the dispersion component is the dominant attractive solute–solvent interaction. This suggests that these force fields predict the correct total strength of dispersion interactions, despite C6 coefficients that are considerably larger than XDM predicts. An analytical expression for the water–methane dispersion energy using XDM dispersion coefficients shows that that higher-order dispersion terms(i.e., C 8 and C 10 ) account for roughly 37.5% of the hydration energy of methane. This suggests that the C 6 dispersion coefficients used in contemporary force fields are</div><div>elevated to account for the neglected higher-order terms. Force fields that include higher-order dispersion interactions could resolve this issue.</div>

Evaluating the London Dispersion Coefficients of Protein Force Fields Using the Exchange-Hole Dipole Moment Model

2018 ◽  
Author(s):  
Evan T. Walters ◽  
Mohamad Mohebifar ◽  
Erin R. Johnson ◽  
Christopher Rowley
Keyword(s):  
Dipole Moment ◽  
Force Fields ◽  
Higher Order ◽  
Side Chain ◽  
Dispersion Interactions ◽  
Dispersion Coefficients ◽  
Hydration Energies ◽  
London Dispersion ◽  
Higher Order Dispersion ◽  
Order Dispersion

<div>London dispersion is one of the fundamental intermolecular interactions involved in protein folding and dynamics. The popular CHARMM36, Amber ff14sb, and OPLS-</div><div>AA force fields represent these interactions through the C6 /r 6 term of the Lennard-Jones potential. The C6 parameters are assigned empirically, so these parameters are</div><div>not necessarily a realistic representation of the true dispersion interactions. In this work, dispersion coefficients of all three force fields were compared to corresponding</div><div>values from quantum-chemical calculations using the exchange-hole dipole moment (XDM) model. The force field values were found to be roughly 50% larger than the XDM values for protein backbone and side-chain models. The CHARMM36 and Amber OL15 force fields for nucleic acids were also found to exhibit this trend. To explore how these elevated dispersion coefficients affect predicted properties, the hydration energies of the side-chain models were calculated using the staged REMD-TI method of Deng and Roux for the CHARMM36, Amber ff14sb, and OPLS-AA force fields. Despite having large C 6 dispersion coefficients, these force fields predict side-chain hydration energies that are in generally good agreement with the experimental values, including for hydrocarbon residues where the dispersion component is the dominant attractive solute–solvent interaction. This suggests that these force fields predict the correct total strength of dispersion interactions, despite C6 coefficients that are considerably larger than XDM predicts. An analytical expression for the water–methane dispersion energy using XDM dispersion coefficients shows that that higher-order dispersion terms(i.e., C 8 and C 10 ) account for roughly 37.5% of the hydration energy of methane. This suggests that the C 6 dispersion coefficients used in contemporary force fields are</div><div>elevated to account for the neglected higher-order terms. Force fields that include higher-order dispersion interactions could resolve this issue.</div>

scholarly journals Brownian Swarm Dynamics and Burgers’ Equation with Higher Order Dispersion

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 57
Author(s):  
Max-Olivier Hongler
Keyword(s):  
Burgers Equation ◽  
Higher Order ◽  
Underlying Structure ◽  
Swarm Dynamics ◽  
Special Cases ◽  
Kink Waves ◽  
Systematic Derivation ◽  
Fifth Order ◽  
Higher Order Dispersion ◽  
Order Dispersion

The concept of ranked order probability distribution unveils natural probabilistic interpretations for the kink waves (and hence the solitons) solving higher order dispersive Burgers’ type PDEs. Thanks to this underlying structure, it is possible to propose a systematic derivation of exact solutions for PDEs with a quadratic nonlinearity of the Burgers’ type but with arbitrary dispersive orders. As illustrations, we revisit the dissipative Kotrweg de Vries, Kuramoto-Sivashinski, and Kawahara equations (involving third, fourth, and fifth order dispersion dynamics), which in this context appear to be nothing but the simplest special cases of this infinitely rich class of nonlinear evolutions.

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