Dear All:<br>      I plan to calculate the phonon of the crystal structure with hexagonal lattice. It spend me one day  to build the crystal structure which was confirmed by Xcrysden. According the experiences of previous e-mails about phonon calculate, the "relax " process of the crystal structure was needed, then I  vc-relaxed the crystal structure and hoped to get a  approving structure in a few hours. But the calculation had took more than 40 thousands second after 14 steps and stopped with the error : too many C- bond were not converged. <br>
<br>input file:<br>&CONTROL<br>                 calculation = 'vc-relax' ,<br>                      outdir = '/root/espresso-4.2/work/Dean/LSAFB/temp/' ,<br>                      wfcdir = '/root/espresso-4.2/work/Dean/LSAFB/wftemp/' ,<br>
                  pseudo_dir = '/root/espresso-4.2/work/Dean/LSAFB/pp/' ,<br>                      prefix = 'LSAF' ,<br>                 lkpoint_dir = .true. ,<br>               etot_conv_thr = 1.0D-5 ,<br>
               forc_conv_thr = 1.0D-4 ,<br>                       nstep = 100 ,<br>                     tstress = .true. ,<br>                     tprnfor = .true. ,<br>                          dt = 20 ,<br>                    dipfield = .true. ,<br>
 /<br> &SYSTEM<br>                       ibrav = 4,<br>                   celldm(1) = 5.0716,<br>                   celldm(3) = 2.0093,<br>                         nat = 18,<br>                        ntyp = 4,<br>                     ecutwfc = 80 ,<br>
                 occupations = 'smearing' ,<br>                     degauss = 0.02 ,<br>                    smearing = 'gaussian' ,<br> /<br> &ELECTRONS<br>            electron_maxstep = 100,<br>                    conv_thr = 1.0D-12 ,<br>
                 mixing_mode = 'plain' ,<br>                 mixing_beta = 0.7D ,<br> /<br> &IONS<br>                ion_dynamics = 'bfgs' ,<br>           pot_extrapolation = 'second_order' ,<br>
           wfc_extrapolation = 'second_order' ,<br>                     upscale = 10D ,<br>                   bfgs_ndim = 1 ,<br>            trust_radius_max = 0.8D0 ,<br>            trust_radius_min = 1.0D-3 ,<br>
            trust_radius_ini = 0.5D ,<br> /<br>ATOMIC_SPECIES<br>   Li    6.94100  Li.pbe-n-van.UPF <br>   Al   26.98154  Al.pbe-sp-van.UPF <br>   Sr   87.62000  Sr.pbe-nsp-van.UPF <br>    F   18.99840  F.pbe-n-van.UPF <br>
ATOMIC_POSITIONS alat <br>   Sr      0.000000000    0.000000000    0.000000000    <br>   Sr      0.000000000    0.000000000    1.004630000    <br>   Li      0.500000000    0.288650000    1.500000000    <br>   Li      0.000000000    0.577370000    0.502310000    <br>
   Al      0.500500000    0.288650000    0.502320000    <br>   Al      0.000000000    0.577380000    1.506900000    <br>    F      0.371500000    0.028400000    0.298380000    <br>    F      0.789650000    0.307530000    0.298380000    <br>
    F      0.338850000    0.530090000    0.298380000    <br>    F      0.661150000    0.530090000    0.706260000    <br>    F      0.628500000    0.028400000    0.706260000    <br>    F      0.210350000    0.307530000    0.706260000    <br>
    F      0.128500000    0.837620000    1.710890000    <br>    F     -0.289650000    0.558500000    1.710890000    <br>    F      0.161150000    0.335930000    1.710890100    <br>    F     -0.161150000    0.335930000    1.303010000    <br>
    F     -0.128500000    0.837620000    1.303010000    <br>    F      0.289650000    0.558500000    1.303010000    <br>K_POINTS automatic <br>  8 8 8   1 1 1 <br><br>I appreciate if one give me some advises to resolve the problem and the reason.<br>
<br>Best regards<br> <br>Wang Di <br>