Practical considerations for transition state finding calculations: Difference between revisions

Revision as of 12:51, 7 February 2024

This page details a few practical considerations for obtaining accurate and reliable transition state energies using VASP.

NEB calculations

Restart with a better guess for the initial and final state configurations

Problem: While performing an NEB calculation, it might appear that there is a point on the band which has lower energy than that of the initial and final state configurations (corresponding to the structures that were placed in the 00 and 0x, where x is the number of IMAGES plus one).

Possible solutions

. Relax the configurations with lower energy. These structures would then correspond to new initial and final configurations. Restart the NEB with these new configurations as the endpoints of the band.
Make sure that the NEB was run with sufficient (and commensurate to the initial and final structures) accuracy. An important requirement in EDIFF, which governs the accuracy of the forces used in the NEB method.

Illustration

@@ Line 4: / Line 4: @@
 === Restart with a better guess for the initial and final state configurations ===
+'''Problem''': While performing an NEB calculation, it might appear that there is a point on the band which has lower energy than that of the initial and final state configurations (corresponding to the structures that were placed in the 00 and 0x, where x is the number of {{TAG|IMAGES}} plus one).
+'''Possible solutions'''
+*. Relax the configurations with lower energy. These structures would then correspond to new initial and final configurations. Restart the NEB with these new configurations as the endpoints of the band.
+* Make sure that the NEB was run with sufficient (and commensurate to the initial and final structures) accuracy. An important requirement in {{TAG|EDIFF}}, which governs the accuracy of the forces used in the NEB method.
+'''Illustration'''