Symmetry change in Gaussian optimization
Posted by isilanes on July 28, 2006
Ever have a Gaussian job die with this error?:
Omega: Change in point group or standard orientation.
It simply means that up to that point the molecule had a certain symmetry (for example, it was planar), and the last optimization step made it jump to another (usually lower) symmetry (for example, bend out of the plane). This is regarded as an error by Gaussian, and thus it aborts the job.
However, sometimes we are not interested in mantaining the symmetry, maybe even the high symmetry of the input was just a coincidence! One way or another, we might be interesting in having this job go on even if the symmetry changes. To do so, we just need to include the following IOp in the input file: