Apparently, QE-7.3.1 does not support some of the tags I was using. The following works: &input ahc_dir = 'ahc_dir_coarse/' flvec = 'PbTe.modes_coarse' ahc_nbnd = 10 amass_amu(1) = 207.2 amass_amu(2) = 127.6 ahc_nbndskip = 0 nk = 1201 nat = 2 nq = 29 nbnd = 12 eta = 0.1 efermi = 6.565 temp_kelvin = 700.0 / Vahid