Enter an atomic species: Cu Enter a cubic lattice type: fcc Enter a model name: SNAP_ZuoChenLi_2019_Cu__MO_931672895580_000 Enter a lattice constant (m): 3.633761629462242e-10 Writing phonon.eq.pckl Writing phonon.0x-.pckl Writing phonon.0x+.pckl Writing phonon.0y-.pckl Writing phonon.0y+.pckl Writing phonon.0z-.pckl Writing phonon.0z+.pckl WARNING, 3 imaginary frequencies at q = ( 0.00, 0.00, 0.00) ; (omega_q = 7.736e-09*i) WARNING, 3 imaginary frequencies at q = ( 0.00, 0.00, 0.00) ; (omega_q = 7.736e-09*i)