Hello everyone,

I have a question concerning the cell optimisation in DMol3. I am carrying out the optimisation of an inorganic structure. To avoid large "jumps" of some atoms, I have considerably reduced the maximal displacement in the input file, from 0.3 Ang to 0.05 Ang. However, when I carry out the cell optimisation, I still observe rather large changes of the cell parameters (by around 0.5 Ang), and the optimisation shows erratic convergence behaviour. This behaviour is visible quite nicely in the attached energy plot of one of these optimisations. I suspect this is caused by overly large changes in the cell parameters when the optimisation is already be close to the minimum. Is there any possibility to decrease the maximal change in cell parameters from one step to the next, e.g. constrain it to 0.1 Ang?

Any comments would be highly appreciated,

Best regards,

Michael