Step 5: Calculating frequencies at the transition state

After every transition state search it is wise to verify that you indeed have one and only one imaginary frequency. For this we will repeat the frequency calculation at the TS geometry:

Make sure you have HCN_TS open in ADFinput
Select the "Frequencies" preset (from the 'Main' panel)
Save with name HCN_Freq2
Run

The calculation is running, should take a few minutes. After the calculation has finished:

Select the SCM → Spectra command

You will be presented with an IR spectrum of the molecule featuring three bands roughly located at 2550, 2050, and (imaginary) -1040 1/cm.

Click on the band at -1040

You should get a movie showing the normal mode corresponding to this frequency, telling us that this is indeed the reaction coordinate we are studying.