Dear all, I'm currently facing an issue with negative frequencies in vibrational analysis. While using the ground state wavefunction in the ground state geometry, frequencies are positive and within the expected range. However, switching to the first excited wavefunction yields a significant number of negative frequencies. Enclosed is my input file for 221 supercells of Fe2O3 with 120 atoms. Your insights and recommendations on this matter would be greatly valued. I've explored various parameters, including: Adjusting the CUTOFF value of TDDFPT from 300 to 600 and 700 Refining the optimized geometry Increasing the TDDFT convergence from 1.0e-5 to 1.0e-6 and 1.0e-7 Despite these efforts, a notable proportion of frequencies persist as negative values. I express my gratitude in advance for your time and assistance. Best regards, Lili -- You received this message because you are subscribed to the Google Groups "cp2k" group. To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp2k+unsubscribe@googlegroups.com">cp2k+unsubscribe@googlegroups.com</a>. To view this discussion on the web visit <a href="https://groups.google.com/d/msgid/cp2k/d23e58da-cdc2-4add-a377-b9751e8f45c6n%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/d23e58da-cdc2-4add-a377-b9751e8f45c6n%40googlegroups.com</a>.