eFieldNormalized

From: Fateme Ghadirian (fateme.ghadirian_at_yahoo.com)
Date: Sat Dec 04 2021 - 07:56:47 CST

Dear NAMD users,
I have a system which contains a fully hydrated bilayer with some particles in the aqueous part of the system. I did not use any free ions in the aqueous part of the system, so I justhave water +Bilayer + water+ some neutral particles in water.  The simulation run is in NPT to represent atmospheric pressure of a natural cell. I want to addconstant electric field in the z direction (bilayer's normal vector) to this system to investigate its possible effects on theparticles and the bilayer. In the following tutorial:
http://bionano.physics.illinois.edu/tutorials/electrostatic-maps-and-ion-conduction

It has used

eFieldOn yes

eField 0.0 0.0 -0.134
In its .conf file to run the constant electric field simulation.

But in the following link

https://www.ks.uiuc.edu/Research/namd/2.10b1/ug/node42.html

The electric field in the .conf file has been applied as follows

eFieldOn yes

eField 0.0 0.0 -0.134

eFieldNormalized yes

By searching in namd-l threads, I have found some opposite explanations about eFieldNormilized, which are given below:
namd-l: Re: Electric field simulation: eFieldNormalized

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namd-l: Re: Electric field simulation: eFieldNormalized

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1) The eFieldNormilized statement is intended to avoid excessive pressure in an NPT simulation in the presence of a constant electric field.

2) The eFieldNormalized does not protect the simulation from “excessive pressure”: it simply defines the electric field with units relative to the unit cell.

I do not understand what eFieldNormalized means and what its function in an electric field simulation is, any help for its clarification would be appreciated.
And also I need to apply constant electric field to my NPT simulation, should I use eFieldNormalized yes or not??? I do not have free ions in my system.
What are the consequences of not using the eFieldNormalized in Simulations?

 

Thanks in advance

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