FREQUENCY: 62.07 I 21.98 I 20.05 I 14.22 I 10.76 I 8.02 I 6.86 I
And in another run:
23.34 I 22.38 I 17.98 I 15.48 I 13.09 I 10.33 I 3.18 I
I read somewhere that low frequencies (especially first or second line) are not vibrations. They should be zero, but are not, due to numerical errors.
Is it correct? Can we safely ignore them? Will the DFT/TDDFT calculations be affected adversely?
In general, is there a thumb rule that we can ignore small frequencies? If yes, then how to decide till which value?
Someone please help.