<div dir="ltr">Dear all, I am trying to obtain the vibrational frequencies of a periodic system of four benzene molecules. When I run the vibrational analysis with no restriction, I obtain the correct number of frequencies (141), but some of them are negative. However, when I restrict the range of the search, I obtain positive wavenumbers, but more frequencies than should be physically present (152). When I try to run the vibrational analysis with tighter convergence but no range, I get an error. The relevant part of the input is below. Any help on obtaining 141 positive numbers is appreciated! &VIBRATIONAL_ANALYSIS &MODE_SELECTIVE EPS_MAX_VAL 0.0000000005 EPS_NORM 0.00000002 &END MODE_SELECTIVE &END VIBRATIONAL_ANALYSIS Returns an error: no frequency, range or involved atoms specified &VIBRATIONAL_ANALYSIS &END VIBRATIONAL_ANALYSIS returns 141 wavenumbers with negatives &VIBRATIONAL_ANALYSIS &MODE_SELECTIVE EPS_MAX_VAL 0.0000000005 EPS_NORM 0.00000002 RANGE 0 50000 &END MODE_SELECTIVE &END VIBRATIONAL_ANALYSIS returns 152 positive numbers Best, Natalie Schieber </div>