Ammm:Mm aplus: Difference between revisions

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=== Introduction ===
=== Introduction ===
One is recommended to read through and understand the background knowledge of polarizable force field AMOEBA, in order to have a better learning experience of the next generation AMOEBA+ force field. As indicated by the name, AMOEBA+ is based on the AMOEBA model with incoporation of essential physical effects that are missing in AMOEBA model. With the short-range charge penetration and charge transfer effects being included, AMOEBA+ potential is able to follow the energy components by the Symmetry Adapted Perturbation Theory (SAPT).   
One is recommended to read through and understand the background knowledge of polarizable force field AMOEBA, in order to have a better learning experience of the next generation AMOEBA+ force field. As indicated by the name, AMOEBA+ is based on the AMOEBA framework with incoporation of essential physical effects that are missing in AMOEBA model. With the short-range charge penetration and charge transfer effects being included, AMOEBA+ potential is able to follow the energy components by the Symmetry Adapted Perturbation Theory (SAPT).   


Below brief description of the SAPT theory is introduced, followed by the specific interactions/physical effects that are incoporated in AMOEBA+ potential. In the last part, brief summary of the current status of the parametrization of the AMOEBA+ force field is given.  
Below brief description of the SAPT theory is introduced, followed by the specific interactions/physical effects that are incoporated in AMOEBA+ potential. In the last part, brief summary of the current status of the parametrization of the AMOEBA+ force field is given.  
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Starting from a dimer AB composed of two monomers, A and B, the interaction energy is computed as:  
Starting from a dimer AB composed of two monomers, A and B, the interaction energy is computed as:  
<math>E_{int} = E_{AB} - E_{A} - E_{B}
</math>


===New Potential Energy Terms===
===New Potential Energy Terms===
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====Charge Penetration====
====Charge Penetration====


====Charge Flux====
====Geometry Dependent Charge Flux====
====Charge Transfer====
====Polarization and Charge Transfer====


===Other Improvements===
===Other Improvements===
====Polarization====


====Polarizability====
====Polarizability====

Revision as of 03:50, 20 July 2022

Introduction

One is recommended to read through and understand the background knowledge of polarizable force field AMOEBA, in order to have a better learning experience of the next generation AMOEBA+ force field. As indicated by the name, AMOEBA+ is based on the AMOEBA framework with incoporation of essential physical effects that are missing in AMOEBA model. With the short-range charge penetration and charge transfer effects being included, AMOEBA+ potential is able to follow the energy components by the Symmetry Adapted Perturbation Theory (SAPT).

Below brief description of the SAPT theory is introduced, followed by the specific interactions/physical effects that are incoporated in AMOEBA+ potential. In the last part, brief summary of the current status of the parametrization of the AMOEBA+ force field is given.

SAPT Method

Intermolecular interactions are small (comparing to the intramolecular interactions). For example, helium dimers at equalibrium only has interaction atoms of -0.02 kcal/mol. However, the intermolecular interactions are important for describing a lot of phenomina in chemistry, physics and biology.

Starting from a dimer AB composed of two monomers, A and B, the interaction energy is computed as:

New Potential Energy Terms

These energy terms are newly added, which means they are not in the AMOEBA model.

Charge Penetration

Geometry Dependent Charge Flux

Polarization and Charge Transfer

Other Improvements

Polarizability

van der Waals

Valence Parameters

Parametrization