query about warnung message

[Florina]

I am unable to understand that what is the meaning behind this message - ################################################################################
# WARNING                                                                      #
#                                                                              #
# The computed TB09 meta-GGA exchange-correlation potential                    #
# diverged in   0.60 % of the simulation volume, and was                       #
# truncated to be in the range [-10.0000,  10.0000] Hartree                    #
#                                                                              #
################################################################################

what changes should i do to avoid this message ? what are the steps which should be written in the script to avoid this warning message ?
thank you for helping !

[Anders Blom]

This is often seen when using MGGA for systems with vacuum. It's usually note a big problem at all, but in case you are using ATK 12.8, you can try the newer version which has some improvements - we are also working on some additional upgrades of MGGA for 14.2 (some may already appear in 13.8.1).

[Florina]

Rev.

I am already using the ATK 13.8 version and still i m getting the warning ! instead of MGGA can i use the GGA-RPBE for calculating optical spectrum ?

[Anders Blom]

It's really just a warning about a small inconsistency in the density in the vacuum, I doubt it will have any influence on your results. You can use any functional you want for the optical spectrum and other calculations. If the accuracy is good or not depends on the system.