Hi,
The official documentation states on the page about SPRING:
Do not use too large values, because this can slow down convergence. The default value usually works quite reliably.
How large is too large? Is -7.5 a too big?
NEB SPRING, how much is too much?
Moderators: Global Moderator, Moderator
-
filipejunqueira
- Newbie
- Posts: 4
- Joined: Tue Jul 12, 2022 8:33 am
-
merzuk.kaltak
- Administrator
- Posts: 278
- Joined: Mon Sep 24, 2018 9:39 am
Re: NEB SPRING, how much is too much?
Hello,
the short answer is: "It depends". Your proposal does not seem completely unreasonable.
This is especially true, if you have a "floppy" band for the default value of -5.
By floppy band, I mean one or more local minima in energy between initial and final state appear.
Here a bigger SPRING value can definitely help to obtain a smooth energy barrier.
Bear in mind though, a too big SPRING value might force your system into wrong transition states.
Alternatively, if you know the image with the highest energy in your NEB the hill climbing method is a good alternative.
Here you would pick this image and relax it using steepest ascent and interpolate the initial and final state through this hill top image.
the short answer is: "It depends". Your proposal does not seem completely unreasonable.
This is especially true, if you have a "floppy" band for the default value of -5.
By floppy band, I mean one or more local minima in energy between initial and final state appear.
Here a bigger SPRING value can definitely help to obtain a smooth energy barrier.
Bear in mind though, a too big SPRING value might force your system into wrong transition states.
Alternatively, if you know the image with the highest energy in your NEB the hill climbing method is a good alternative.
Here you would pick this image and relax it using steepest ascent and interpolate the initial and final state through this hill top image.