[Pw_forum] The atomic displacements By QE and Abinit

[昶棘汐]

Dear all

i have run the program ph.x and got the outfile  *.dyn_G. from what I
understand, the diagonalized dynamical matrix should give displacements of
each atom. and each column gives the real and imaginary components of the
displacements .so in the output

omega( 1) =      -0.294635 [THz] =      -9.828034 [cm-1]
 (  0.000006  0.000000 -0.000003  0.000000  0.288697  0.000000 )
 (  0.000000  0.000000  0.000007  0.000000  0.288697  0.000000 )
 ( -0.000006  0.000000 -0.000003  0.000000  0.288697  0.000000 )
 (  0.000010  0.000000 -0.000006  0.000000  0.288654  0.000000 )
 (  0.000000  0.000000  0.000011  0.000000  0.288654  0.000000 )
 ( -0.000010  0.000000 -0.000006  0.000000  0.288654  0.000000 )
 (  0.000006  0.000000 -0.000003  0.000000  0.288697  0.000000 )
 (  0.000000  0.000000  0.000007  0.000000  0.288697  0.000000 )
 ( -0.000006  0.000000 -0.000003  0.000000  0.288697  0.000000 )
 (  0.000010  0.000000 -0.000006  0.000000  0.288654  0.000000 )
 (  0.000000  0.000000  0.000011  0.000000  0.288654  0.000000 )
 ( -0.000010  0.000000 -0.000006  0.000000  0.288654  0.000000 )

however it is different from the the outcome of Abinit

Eigendisplacements
 (will be given, for each mode : in cartesian coordinates
   for each atom the real part of the displacement vector,
   then the imaginary part of the displacement vector)
  Mode number    1   Energy    0.000000E+00
 Attention : low frequency mode.
   (Could be unstable or acoustic mode)
;  1  0.00000000E+00  0.00000000E+00 -2.05634696E-03
;     0.00000000E+00  0.00000000E+00  0.00000000E+00
;  2  0.00000000E+00  0.00000000E+00 -2.05634695E-03
;     0.00000000E+00  0.00000000E+00  0.00000000E+00
;  3  0.00000000E+00  0.00000000E+00 -2.05634695E-03
;     0.00000000E+00  0.00000000E+00  0.00000000E+00
;  4  0.00000000E+00  0.00000000E+00 -2.05634696E-03
;     0.00000000E+00  0.00000000E+00  0.00000000E+00
;  5  0.00000000E+00  0.00000000E+00 -2.05634696E-03
;     0.00000000E+00  0.00000000E+00  0.00000000E+00
;  6  0.00000000E+00  0.00000000E+00 -2.05634696E-03
;     0.00000000E+00  0.00000000E+00  0.00000000E+00
;  7  0.00000000E+00  0.00000000E+00 -2.05634696E-03
;     0.00000000E+00  0.00000000E+00  0.00000000E+00
;  8  0.00000000E+00  0.00000000E+00 -2.05634695E-03
;     0.00000000E+00  0.00000000E+00  0.00000000E+00
;  9  0.00000000E+00  0.00000000E+00 -2.05634695E-03
;     0.00000000E+00  0.00000000E+00  0.00000000E+00
; 10  0.00000000E+00  0.00000000E+00 -2.05634696E-03
;     0.00000000E+00  0.00000000E+00  0.00000000E+00
; 11  0.00000000E+00  0.00000000E+00 -2.05634696E-03
;     0.00000000E+00  0.00000000E+00  0.00000000E+00
; 12  0.00000000E+00  0.00000000E+00 -2.05634696E-03
;     0.00000000E+00  0.00000000E+00  0.00000000E+00

how could i understand it .why the QE and Abinit give the different outcome
. i hope some help . and thanks in advance

tanyci
nankai university , tianjin
china
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