[Pw_forum] A question about Gamma-point calculation

[Chaohao Hu]

I am trying to do phonon calculation about lanthanum hydride. For 
a small cell only containing 6 atoms (LaNi5), I can obtain good results
of scf and phonon calculations. But for a larger supercell (LaNi5-xMx and
 its hydrides), this task will stop when calculating the fifth or sixth 
irreducible representations. Why???
Can you give me some hints about this problem? How to resolve it?
In my *.phG.out file, some informations are described as following,
====================================================
     ......
     Representation    33      2 modes - To be done

     Representation    34      2 modes - To be done

     Representation    35      1 modes - To be done

     Representation    36      1 modes - To be done
     PHONON       : 53m35.87s CPU time
     ......


     Representation #  5 modes #   5  6

     Self-consistent Calculation
 
     Pert. #  1: Fermi energy shift (Ryd) =    0.0000    0.0000
     Pert. #  2: Fermi energy shift (Ryd) =    0.0000    0.0000

      iter #   1 total cpu time : 10373.3 secs   av.it.:   7.5
      thresh= 0.100E-01 alpha_mix =  0.700 |ddv_scf|^2 =  0.162E-05
====================================================

Thanks in advance.
Best regards,
Chaohao

============================================================
Dr.Ch.H.Hu
Institute of Metal Research,Chinese Academy of Sciences--IMR
Wenhua Road, 72
110016, Shenyang, Liaoning (China)
Phone: +086-024-23971641
Email: chhu at imr.ac.cn