I was assigned a multistep task by my professor so I first made the molecule with ChemDraw, then I ran an optimisation using B3LYP/6-31G. I then ran a frequency scan and checked for any imaginary frequencies. There were no negative frequencies and my understanding is that this means that Gaussian optimised the structure to a global minimum, as opposed to a local minimum or saddle point etc. The next step of my task was to run a stability=opt scan on the structure to "check the stability of the ground state wavefunction". Unfortunately, it turns out that the wavefunction isn't stable. Problem is I don't know what that means, let alone how to fix it. Maths isn't my strongest field so the Schrodinger equation confuses the hell out of me but my understanding is that a wavefunction represents the probability of finding electrons in 3D space. What exactly is a "ground state" wavefunction? Or a better question: what is a non ground state wave function? I'm guessing an example of an excited state wavefunction would represent the electron distribution of a molecule after I beam it with UV-Vis radiation so that some of its electrons jump to higher energy levels, have I got the right idea? If the ground state wavefunction for my molecule is instable, does that mean the optimisation failed? If so, how can I correct it?