AFIRサンプル

Energy oscillating issue during geometry optimization

When we are doing a energy minimization in Gaussian 09, one of the issues that rise are that the energy of minimization steps will start to oscillate and never converge until one kills the calculation job or it passes a huge number of steps, wasting a computational time. So, our question is: can this kind of behavior happen in the GRRM during the minimization performed during a AFIR calculation (or other GRRM calculation that requires the minimization algorithm) that we have to keep an eye on it to avoid wasting computer time in a calculation that gets "derailed " from its original purpose?, in other words, what are those things that we should watch out during the calculation to know that something is wrong and we have to reset or change something because the calculation won't stop but it is going wrong? 

Thank you very much.

  • Re:
    Satoshi Maeda

    GRRM uses a Quasi-Newton algorithm in geometry optimization. Therefore, common problems in Quasi-Newton algorithms also occur in GRRM calculations. In AFIR path calculations, such a case is detected and the path calculation will be terminated before wasting computational time. It is also noted that such paths are not just discarded but are processed like other paths to find TSs along the paths.