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["徐" <lanqingxu@fjnu.edu.cn>]

  Dear forum users,
I'm following tutor of RF2 and calculating phonon dispersion curve and PDOS for PbTe. The psudopotential files are 82pb.pspnc and 52te.pspnc(LDA), ecut 30, ngkpt 3*4.  The curious thing is that abinit gave out negative  Phonon energy and frequency in the output file as following;

Phonon wavevector (reduced coordinates) :  0.00000  0.00000  0.00000
 Phonon energies in Hartree :
  -2.656610E-07 -2.656575E-07 -2.656473E-07  2.114512E-04  2.114512E-04
   2.114512E-04

But after analyzed ddb anaddb gave out zero Phonon energy and frequency at gamma.

  Phonon at Gamma, with non-analyticity in the
  direction (cartesian coordinates)  1.00000  0.00000  0.00000
 Phonon energies in Hartree :
   0.000000E+00  0.000000E+00  0.000000E+00  2.114513E-04  2.114514E-04
   4.680436E-04
 Phonon frequencies in cm-1    :
-  0.000000E+00  0.000000E+00  0.000000E+00  4.640819E+01  4.640822E+01
-  1.027237E+02

Is it natural or not?
What's more, I use prtdos 1 to print the PDOS. But the output PHDOS has omiga from -0.29933    to 17.18245  and the total distribution isn't right. Is there anything wrong?
The two input files are as following. Any comments will be appreciated. Thank you in advance.

Best regards,
shelleny

#####abinis input file:#####################
ndtset 10 
#Datasets 1 : GS
getwfk1 0
kptopt1 1
nqpt1 0
tolvrs1 1.0d-18
rfphon1 0
#q vectors
nqpt 1
     qpt2   0.00000000E+00  0.00000000E+00  0.00000000E+00
     qpt3   0.00000000E+00  0.00000000E+00  0.00000000E+00
     qpt4   2.50000000E-01  0.00000000E+00  0.00000000E+00
     qpt5   5.00000000E-01  0.00000000E+00  0.00000000E+00
     qpt6   2.50000000E-01  2.50000000E-01  0.00000000E+00
     qpt7   5.00000000E-01  2.50000000E-01  0.00000000E+00
     qpt8  -2.50000000E-01  2.50000000E-01  0.00000000E+00
     qpt9   5.00000000E-01  5.00000000E-01  0.00000000E+00
     qpt10 -2.50000000E-01  5.00000000E-01  2.50000000E-01
#Dataset 2 : ddk
 rfelfd2   2
 rfphon2   0
 kptopt2   2
 iscf2     -3
tolvrs2 0.0
tolwfr2 1.0d-22
#Dataset 3: electric field + phonon response at gamma
 rfelfd3  3
 getddk3  -1
 kptopt3   2
#Dataset 4-74: phonon perturb
getwfk 1
kptopt 3
rfphon 1
rfatpol 1 2
rfdir 1 1 1
tolvrs 1.0d-8
# non-spinor wavefunctions, without SO coupling
 nband   5
#Common data
 acell 3*4.5672  Angstroms
 angdeg 60 60 60
 chkprim 0
 ecut  30
 natom  2
 ntypat  2
 typat  1 2
 xred    3*0.0d0
         3*0.5d0
 znucl 82 52
#Kpt grid
ngkpt 3*4
nshiftk 4
shiftk 0.5 0.5 0.5
       0.5 0   0
       0   0.5 0
       0   0   0.5
#SCF
 iscf  5
 diemac 10
 nstep    100


######anaddb  input file#########################
!Flags
 dieflag   1     ! Frequency-dependent Dielectric tensor flag
 ifcflag   1     ! Interatomic force constant flag
 thmflag   1     ! Thermodynamical properties flag
!Wavevector grid number 1 (coarse grid, from DDB)
  brav    1      ! Bravais Lattice : 1-S.C., 2-F.C., 3-B.C., 4-Hex.)
  ngqpt   4  4  4   ! Monkhorst-Pack indices
  nqshft  1         ! number of q-points in repeated basic q-cell
  q1shft  3*0.0

!Effective charges
     asr   1     ! Acoustic Sum Rule. 1 => imposed asymetrically
  chneut   1     ! Charge neutrality requirement for effective charges.

!Interatomic force constant info
  dipdip  1      ! Dipole-dipole interaction treatment
  ifcana  1      ! Analysis of the IFCs
  ifcout 16      ! Number of IFC's written in the output, per atom
  natifc  2      ! Number of atoms in the cell for which ifc's are analysed
   atifc  1 2    ! List of atoms

!Phonon band structure output for band2eps - See note near end for
! dealing with gamma LO-TO splitting issue.
   eivec  4
   prtdos 1

!Wavevector list number 1 (Reduced coordinates and normalization factor)        
  nph1l    41      ! number of phonons in list 1                            

  qph1l   0.5000  0.5000  0.5000   1.0    !(L point)
          0.5500  0.5500  0.5500   1.0
          0.6000  0.6000  0.6000   1.0
          0.6500  0.6500  0.6500   1.0
          0.7000  0.7000  0.7000   1.0
          0.7500  0.7500  0.7500   1.0
          0.8000  0.8000  0.8000   1.0
          0.8500  0.8500  0.8500   1.0
          0.9000  0.9000  0.9000   1.0
          0.9500  0.9500  0.9500   1.0
          1.0000  1.0000  1.0000   1.0    !(gamma point)
          0.9500  0.9500  1.0000   1.0
          0.9000  0.9000  1.0000   1.0
          0.8500  0.8500  1.0000   1.0
          0.8000  0.8000  1.0000   1.0
          0.7500  0.7500  1.0000   1.0
          0.7000  0.7000  1.0000   1.0
          0.6500  0.6500  1.0000   1.0
          0.6000  0.6000  1.0000   1.0
          0.5500  0.5500  1.0000   1.0
          0.5000  0.5000  1.0000   1.0    !(X point)
          0.4875  0.4875  0.9750   1.0
          0.4750  0.4750  0.9500   1.0
          0.4625  0.4625  0.9250   1.0
          0.4500  0.4500  0.9000   1.0
          0.4375  0.4375  0.8750   1.0
          0.4250  0.4250  0.8500   1.0
          0.4125  0.4125  0.8250   1.0
          0.4000  0.4000  0.8000   1.0
          0.3875  0.3875  0.7750   1.0
          0.3750  0.3750  0.7500   1.0    !(K point)
          0.3375  0.3375  0.6750   1.0
          0.3000  0.3000  0.6000   1.0
          0.2625  0.2625  0.5250   1.0
          0.2250  0.2250  0.4500   1.0
          0.1875  0.1875  0.3750   1.0
          0.1500  0.1500  0.3000   1.0
          0.1125  0.1125  0.2250   1.0
          0.0750  0.0750  0.1500   1.0
          0.0375  0.0375  0.0750   1.0
          0.0000  0.0000  0.0000   1.0    !(gamma point)
         
!Wavevector list number 2 (Cartesian directions for non-analytic gamma phonons)
  nph2l    1       ! number of directions in list 2

  qph2l   1.0  0.0  0.0    0.0

!Wavevector grid number 2 (series of fine grids, extrapolated from interat forces)
  ng2qpt   20 20 20  ! sample the BZ up to ngqpt2
  ngrids   5         ! number of grids of increasing size
  q2shft   3*0.0

!Thermal information
  nchan   1250   ! # of channels for the DOS with channel width 1 cm-1
  nwchan  5      ! # of different channel widths from this integer down to 1 cm-1
  thmtol  0.030  ! Tolerance on thermodynamical function fluctuations
  ntemper 90     ! Number of temperatures
  temperinc 2.  ! Increment of temperature in K for temperature dependency
  tempermin 4.  ! Minimal temperature in Kelvin

# This line added when defaults were changed (v5.3) to keep the previous, old behaviour
  symdynmat 0