Freq Output

After the freq task finish, run ~/gaussian/freq_thermal.py freq-log-file-name to calculate entropy and enthalpy based on the frequecies. Or run for i in *.log; do ~/gaussian/freq_thermal.py $i; done to get the output for all log files in the current directory.

  • If the task completes successfully, you will see the output file named with “*_freq.csv”.
  • A common error is the first several frequencies are negative. If so, open the log file with GaussView, right click-> Results -> Vibrations, find the mode with negative frequency and click “Start Animation”. Tweak the molecule along the vibration direction and save the molecule in the Gaussian input format. Reoptmize it and Recompute the frequency.

Gibbs Energy

To compute Gibbs Energy, we need a file that has all structures’ name and corresponding Hatree Fock energies, and all corresponding freq.csv files that created by “freq_thermal.py”.

  1. Copy all Gaussian optimized output files (opt.log) to the same folder and run ~/gaussian/HFenergies.py to get the “HFenergies.csv”.
  2. Copy all corresponding “*_freq.csv” to that directory. If the structure name in “HFenergies.csv” is “x”, the file name of its frequency file should be “x_freq.csv”.
  3. Type ~/gaussian/GibbsEnergy.py HFenergies.csv to get “gibbs.csv”.