I am trying to reproduce the phonon dispersion of fluorinated arsenene (first obtained by Li Chen et al.; Sci Rep 6, 28487 (2016)) using quantum espresso. At first I have relaxed the structure and then performed SCF calculation with 15x15x1 MP grid and ultrasoft pseudopotentials. Then I performed the phonon calculations with 4x4x1 q point mesh. But the result I have obtained is far from the accurate one (attached Figure 1). I have also attached my phonon calculation input files here (Figure 2). Can someone please give me suggestions about what changes should be made in my input files to obtain the correct result? Thanks in advance.