<div dir="ltr">Dear users<div style>I have a question about the output of vc-relax. when I run vc-relax for orthorhombic structure, the output celldms are so different from experimental data. forexample celldm(1) is 8.896 bohr from experimental data, but the output celldm(1) from vc-relax is 6.960 bohr.</div>
<div style>my input file is:</div><div style><div>&CONTROL</div><div>      calculation='vc-relax'</div><div>     restart_mode ='from_scratch',</div><div>           outdir = '/home/izadi/tmp/vc.orthorhombic',</div>
<div>           prefix = 'VC',</div><div>       pseudo_dir = '/home/izadi/pseudo/',</div><div>         tstress  = .TRUE.,</div><div>         tprnfor  = .TRUE., </div><div> /</div><div> &SYSTEM</div><div>
        ibrav = 9, </div><div>    celldm(1) = 8.896,</div><div>    celldm(2) = 1.051,</div><div>    celldm(3) = 0.998,</div><div>           nat= 8,  </div><div>         ntyp = 2,</div><div>        nspin = 1,</div><div>      ecutwfc = 30,</div>
<div>      ecutrho = 120,</div><div>  occupations = 'smearing',</div><div>       degauss= 0.01,</div><div>&electrons</div><div>     conv_thr=1.D-5,</div><div>     mixing_beta=0.7,</div><div> /</div><div>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     &ELECTRONS</div>
<div>         conv_thr = 1.D-6,</div><div>      mixing_beta = 0.7,</div><div>/</div><div> &IONS</div><div>  ion_dynamics = 'damp'</div><div>/</div><div> &CELL</div><div> cell_dynamics='damp-w'</div>
<div> /</div><div>ATOMIC_SPECIES </div><div> Ga    69.72   Ga.pz-bhs.UPF </div><div>  P     30.974  P.pz-bhs.UPF</div><div><br></div><div>ATOMIC_POSITIONS   (crystal) </div><div> Ga     0.000     0.624    0.250</div><div>
 Ga     0.000     0.376    0.750 </div><div> Ga     0.500     0.124    0.250</div><div> Ga     0.500     0.876    07500</div><div> P      0.000     0.152    0.250</div><div> P      0.000     0.848    0.750</div><div> P      0.500     0.652    0.250</div>
<div> P      0.500     0.348    0.750   </div><div>K_POINTS   (automatic)</div><div>4 3 5    0  0  0</div><div><br></div></div></div>