scholarly journals The Necessity of Periodic Boundary Conditions for the Accurate Calculation of Crystalline Terahertz Spectra

2020 ◽  
Author(s):  
Peter Banks ◽  
Luke burgess ◽  
Michael Ruggiero
Keyword(s):  
Boundary Conditions ◽  
Gas Phase ◽  
Long Range ◽  
Periodic Boundary ◽  
Terahertz Spectroscopy ◽  
Good Practice ◽  
Periodic Boundary Conditions ◽  
Spectroscopic Technique ◽  
Long Range Interactions ◽  
Phase Cluster

Terahertz vibrational spectroscopy has emerged as a powerful spectroscopic technique, providing valuable information regarding long-range interactions -- and associated collective dynamics -- occurring in solids. However, the terahertz sciences are relatively nascent, and there have been significant advances over the last several decades that have profoundly influenced the interpretation and assignment of experimental terahertz spectra. Specifically, because there do not exist any functional group or material-specific terahertz transitions, it is not possible to interpret experimental spectra without additional analysis, specifically, computational simulations. Over the years simulations utilizing periodic boundary conditions have proven to be most successful for reproducing experimental terahertz dynamics, due to the ability of the calculations to accurately take long-range forces into account. On the other hand, there are numerous reports in the literature that utilize gas phase cluster geometries, to varying levels of apparent success. This perspective will provide a concise introduction into the terahertz sciences, specifically terahertz spectroscopy, followed by an evaluation of gas phase and periodic simulations for the assignment of crystalline terahertz spectra, highlighting potential pitfalls and good practice for future endeavors.

scholarly journals The Necessity of Periodic Boundary Conditions for the Accurate Calculation of Crystalline Terahertz Spectra

2020 ◽  
Author(s):  
Peter Banks ◽  
Luke burgess ◽  
Michael Ruggiero
Keyword(s):  
Boundary Conditions ◽  
Gas Phase ◽  
Long Range ◽  
Periodic Boundary ◽  
Terahertz Spectroscopy ◽  
Good Practice ◽  
Periodic Boundary Conditions ◽  
Spectroscopic Technique ◽  
Long Range Interactions ◽  
Phase Cluster

Terahertz vibrational spectroscopy has emerged as a powerful spectroscopic technique, providing valuable information regarding long-range interactions -- and associated collective dynamics -- occurring in solids. However, the terahertz sciences are relatively nascent, and there have been significant advances over the last several decades that have profoundly influenced the interpretation and assignment of experimental terahertz spectra. Specifically, because there do not exist any functional group or material-specific terahertz transitions, it is not possible to interpret experimental spectra without additional analysis, specifically, computational simulations. Over the years simulations utilizing periodic boundary conditions have proven to be most successful for reproducing experimental terahertz dynamics, due to the ability of the calculations to accurately take long-range forces into account. On the other hand, there are numerous reports in the literature that utilize gas phase cluster geometries, to varying levels of apparent success. This perspective will provide a concise introduction into the terahertz sciences, specifically terahertz spectroscopy, followed by an evaluation of gas phase and periodic simulations for the assignment of crystalline terahertz spectra, highlighting potential pitfalls and good practice for future endeavors.

The necessity of periodic boundary conditions for the accurate calculation of crystalline terahertz spectra

2021 ◽  
Author(s):  
Peter A. Banks ◽  
Luke Burgess ◽  
Michael T Ruggiero
Keyword(s):  
Boundary Conditions ◽  
Long Range ◽  
Vibrational Spectroscopy ◽  
Periodic Boundary ◽  
Periodic Boundary Conditions ◽  
Spectroscopic Technique ◽  
Accurate Calculation ◽  
Collective Dynamics ◽  
Long Range Interactions

Terahertz vibrational spectroscopy has emerged as a powerful spectroscopic technique, providing valuable information regarding long-range interactions - and associated collective dynamics - occurring in solids. However, the terahertz sciences are...

NONEXTENSIVE MICROSCOPIC BEHAVIOR OF LONG-RANGE INTERACTING PARTICLES IN PERIODIC MEDIA

2000 ◽  
Vol 11 (03) ◽  
pp. 629-634 ◽  
Author(s):  
SERGIO CURILEF
Keyword(s):  
Boundary Conditions ◽  
Long Range ◽  
Periodic Boundary ◽  
Present Model ◽  
Periodic Boundary Conditions ◽  
The Other ◽  
Attractive Potential ◽  
Periodic Media ◽  
Interacting Particles ◽  
Other Hand

This work presents a possible way to study the long-range interacting particles in finite-infinite (mesoscopic-macroscopic) systems with periodic boundary conditions. A symmetric lattice and their contributions over all space are used in the problem. In the present model, we assume that at long distances, the two-body attractive potential decays as a 1/rα law. We verified that the potential in any particle converges (diverges) when the interactions are short(long)-ranged. On the other hand, forces in any particle converge rapidly in all cases. However, we adopt a nonextensive scaling and we guarantee that the potential converges anywhere.

Molecular Dynamics Using Non-Variational Polarizable Force Fields: Theory, Periodic Boundary Conditions Implementation and Application to the Bond Capacity Model

2019 ◽  
Author(s):  
Pier Paolo Poier ◽  
Louis Lagardere ◽  
Jean-Philip Piquemal ◽  
Frank Jensen
Keyword(s):  
Boundary Conditions ◽  
Periodic Boundary ◽  
Force Fields ◽  
Periodic Boundary Conditions ◽  
Computational Effort ◽  
Polarizable Force Fields ◽  
Energy Models ◽  
Capacity Model ◽  
Energy Gradient ◽  
Polarization Models

<div> <div> <div> <p>We extend the framework for polarizable force fields to include the case where the electrostatic multipoles are not determined by a variational minimization of the electrostatic energy. Such models formally require that the polarization response is calculated for all possible geometrical perturbations in order to obtain the energy gradient required for performing molecular dynamics simulations. </p><div> <div> <div> <p>By making use of a Lagrange formalism, however, this computational demanding task can be re- placed by solving a single equation similar to that for determining the electrostatic variables themselves. Using the recently proposed bond capacity model that describes molecular polarization at the charge-only level, we show that the energy gradient for non-variational energy models with periodic boundary conditions can be calculated with a computational effort similar to that for variational polarization models. The possibility of separating the equation for calculating the electrostatic variables from the energy expression depending on these variables without a large computational penalty provides flexibility in the design of new force fields. </p><div><div><div> </div> </div> </div> <p> </p><div> <div> <div> <p>variables themselves. Using the recently proposed bond capacity model that describes molecular polarization at the charge-only level, we show that the energy gradient for non-variational energy models with periodic boundary conditions can be calculated with a computational effort similar to that for variational polarization models. The possibility of separating the equation for calculating the electrostatic variables from the energy expression depending on these variables without a large computational penalty provides flexibility in the design of new force fields. </p> </div> </div> </div> </div> </div> </div> </div> </div> </div>

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