Error in application of minimum_image and rfo

GULP
1

Hi,

I have been optimizing my metal-organic framework system with the presence and absence of guests for adsorption calculation. I am getting the following error with the application of the keywords minimum_image

  1. "NoConditionsForMin: ‘Conditions for a minimum have not been satisfied. However, no lower point can be found - treat results with caution unless gradient norm is small (less than 0.1)’
    and if i use the keyword rfo i am getting the errors
  2. ’ Maximum number of function calls has been reached ’
  3. ’ Too many failed attempts to optimize '.

I would like to know the reason behind these errors. Any suggestions to rectify them would be helpful.

Thanks.

2

These errors are all commonly associated with a discontinuous energy surface. This means you need to ensure that you make things as smooth as possible by tapering the ends of your potentials and/or using longer cutoffs & looking for any other similar issues in the force field you have defined. Note that there is no need to use the minimum image convention in GULP & so you might want to try without this.