I am trying to optimize a 48 atom heterostructure using wB97XD hybrid and 6-311G++(d,p) basis set in Gaussian 16. It's been more than 24 hours and the output file is saying 'no special action if energy rises' only. What should I do? Kill the process? Or wait? Number of processors are 10 in the workstation.
Until an error message is received, you must wait and ignore the diagnostic messages. However, there is a chance that the task will not be solved. The problem is that the use of diffuse functions in the basis set significantly worsens the convergence of the SCF. Therefore, I would recommend that you first carry out calculations in the basis without diffuse functions (6-311G(d, p)), and only then, having a good guess, use it for further calculations (guess=read).