Why does dynamical_matrix return negative values?


When following the example for the dynamical_matrix command (here) and turning on the minimization flag, there are substantial negative values. Here are the first six lines of the output file that’s generated when I run it:

5407.73126648 0.60396688 0.00000175
-1276.30761693 -861.92746902 -861.81428983
-193.16889479 0.00650038 -0.00000008
-1276.30761624 -861.92746857 861.81429082
-193.17584859 -0.02457904 0.00000000
-1276.12053965 861.59922389 -861.65460775

This shouldn’t be the case for a minimized configuration, right? Shouldn’t the elements of the Hessian should be positive at a minimum? The matrix’s eigenvalues are negative as well (using this tool). The first 8 are:


I have tried the command on other systems as well, and there have been negative values in every case. I’m not really sure what to make of this.

Perhaps @charlessievers can comment on this.