UT theoretical chemistry code forum

Hello Dr. Graeme

I am using CI-NEB with IOPT=3 (QM method) option to obtain a TS. After my NEB converges, is it okay to directly proceed and check for the imaginary frequency in the highest energy image of the profile (or) is it important to further continue this NEB calculation by changing the optimizer from IOPT=3 to IOPT=1 or 2? Your suggestions regarding this shall be helpful.

Thanks in advance

If you are happy with the force on the climbing image, you are set to do a frequency calculation - no need to do another calculation.

Thanks, Dr. Henkelman.