[QE-users] raman with phcg

[Aleksandra Oranskaia]

Dear Paolo,

Input is the same as described in the 1st message - see
.../PHonon/example12 (qe-6.7)
- exactly the same
- modified for SiH4 put the middle of the ibrav = 1 with A = 20.0
- with lraman = .True., deltatau = 0.01.



First one terminates okay, but results do not look nice, and the same (as
in other 2 cases) erroe appears:

" ***  Starting Conjugate Gradient minimization         ***
   *** Conjugate Gradient minimization not converged after  50 iterations
 residual norm |Ax-b|^2 : 0.2455E+00
 ***  pol. #   1 :  50 iterations
   *** Conjugate Gradient minimization not converged after  50 iterations
 residual norm |Ax-b|^2 : 0.2697E+00
 ***  pol. #   2 :  50 iterations
   *** Conjugate Gradient minimization not converged after  50 iterations
 residual norm |Ax-b|^2 : 0.2214E-01
 ***  pol. #   3 :  50 iterations

ATOMIC_POSITIONS
Si            0.0000000000        0.0000000000        0.0000000000
H             0.1285307440        0.1285307440        0.1285307440
H            -0.1285307440       -0.1285307440        0.1285307440
H            -0.1285307440        0.1285307440       -0.1285307440
H             0.1285307440       -0.1285307440       -0.1285307440



     dielectric constant                    polarizability (A^3)
 22.258419 -0.015166 -0.013281       0.133927E+02 -0.772596E-01
-0.676541E-01
 -0.021430 22.246210 -0.039084      -0.109170E+00  0.133917E+02
-0.199103E+00
  0.026548  0.038463 22.274244       0.135239E+00  0.195939E+00
 0.133939E+02

     z*( 1)   -4.3411   -0.0029   -0.1075
              -0.0073   -4.3485    0.1224
               0.0366   -0.0246   -4.2874

     z*( 2)    0.8033   -0.4537   -0.4544
              -0.4581    0.7774   -0.4578
              -0.4751   -0.4780    0.8034

     z*( 3)    0.8033   -0.4537    0.4544
              -0.4581    0.7774    0.4578
               0.4751    0.4780    0.8034

     z*( 4)    0.8033    0.4537   -0.4544
               0.4581    0.7774    0.4578
              -0.4751    0.4780    0.8034

     z*( 5)    0.8033    0.4537    0.4544
               0.4581    0.7774   -0.4578
               0.4751   -0.4780    0.8034

 ***  Starting Conjugate Gradient minimization         ***
     d2ion: alpha =   0.50
 ***  mode #   1 : using asr
 ***  mode #   2 : using asr
 ***  mode #   3 : using asr
   *** Conjugate Gradient minimization not converged after  50 iterations
 residual norm |Ax-b|^2 : 0.3928E-03
 ***  mode #   4 :  50 iterations
   *** Conjugate Gradient minimization not converged after  50 iterations
 residual norm |Ax-b|^2 : 0.3821E-03
 ***  mode #   5 :  50 iterations
   *** Conjugate Gradient minimization not converged after  50 iterations
 residual norm |Ax-b|^2 : 0.3925E-03
 ***  mode #   6 :  50 iterations
 ***  mode #   7 : using symmetry
 ***  mode #   8 : using symmetry
 ***  mode #   9 : using symmetry
 ***  mode #  10 : using symmetry
 ***  mode #  11 : using symmetry
 ***  mode #  12 : using symmetry
 ***  mode #  13 : using symmetry
 ***  mode #  14 : using symmetry
 ***  mode #  15 : using symmetry
  Symmetry violation  sum_ij |D_ij-D_ji| :       3.158358
  ASR violation  sum_i |D_ij| :       2.908104
     diagonalizing the dynamical matrix ...


 **************************************************************************
     omega(  1) =-41.789471 [THz] =*********** [cm-1]
     omega(  2) =-41.747411 [THz] =*********** [cm-1]
     omega(  3) =-41.067104 [THz] =*********** [cm-1]
     omega(  4) =-41.026620 [THz] =*********** [cm-1]
     omega(  5) =-40.999019 [THz] =*********** [cm-1]
     omega(  6) =-40.464473 [THz] =*********** [cm-1]
     omega(  7) =-40.425285 [THz] =*********** [cm-1]
     omega(  8) =-40.404738 [THz] =*********** [cm-1]
     omega(  9) = -0.002473 [THz] =  -0.082484 [cm-1]
     omega( 10) = -0.000001 [THz] =  -0.000021 [cm-1]
     omega( 11) =  0.006516 [THz] =   0.217342 [cm-1]
     omega( 12) = 44.041877 [THz] =1469.078889 [cm-1]
     omega( 13) = 44.042544 [THz] =1469.101146 [cm-1]
     omega( 14) = 44.051925 [THz] =1469.414038 [cm-1]
     omega( 15) = 46.311307 [THz] =1544.778927 [cm-1]
"

On Mon, Jun 13, 2022 at 8:29 PM Paolo Giannozzi <paolo.giannozzi at uniud.it>
wrote:

> On 13/06/2022 15:47, Aleksandra Oranskaia wrote:
>
> > I found out that even without Raman cross sections, phcg gives some
> > troubles with CG minimization [...] >     *** Conjugate Gradient
> minimization not converged after  50
> iterations
>
> hard to say anything sensible, with so little information available
>
> Paolo
> --
> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>


-- 
Best wishes,
Alex (she/her/hers),
phd candidate in chemical sciences
'I.. a universe of atoms, an atom in the universe' (Richard P. Feynman)
https://cpms.kaust.edu.sa/

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