UT theoretical chemistry code forum

Hi! I was carrying out dynamic matrix calculation on a simple molecule CO and I have obtained the following frequencies:

695.430122 cm^{-1} ... 1
24.663956 cm^{-1} ... 1
0.000005 cm^{-1} ... 1
0.000004 cm^{-1} ... 0
60.734582 cm^{-1} ... 0
1614.673958 cm^{-1} ... 0

So which of these are translational, rotational, and vibrational modes? Also, what do the "1"s and "0"s on the right hand side stand for?

The 1 indicates a negative mode and 0 is positive. You can look at them, using (for example) our modes2xyz script. I expect modes 2-4 are translational, 5 is a wag/bend/hindered rotation and 6 is a stretch. I would be concerned about the first negative mode with a significant value.