SCPH relaxation

[RicardoCecconello]

Dear Dr. Tadano,

I'm trying to do a SCPH relaxation of the cell and the positions, but at the first temperature (0 K), on Structure loop 2, the calculation doesn't converge and shows a warning that the modes have zero frequencies.
The SCPH, CELL, RELAX, DISPLACE and STRAIN block on the input are as follows:

&scph
 SELF_OFFDIAG = 1 
 MAXITER = 1000
 MIXALPHA = 0.1
 KMESH_INTERPOLATE = 4 4 2 
 KMESH_SCPH = 4 4 2 
 LOWER_TEMP = 0 
 TOL_SCPH = 1.0e-11

 RELAX_STR = 2
/

&cell 
 1.889726
2.67289102017      1.58558405284      0.0
-2.67289102017     1.58558405284      0.0
-1.65942269596     4.48533745409e-16  7.13467458674
/

&relax
  RELAX_ALGO = 2
  MAX_STR_ITER = 1000

  STAT_PRESSURE = 0.0 # GPa

  COORD_CONV_TOL = 1.0e-5
  MIXBETA_COORD = 0.4
  CELL_CONV_TOL = 1.0e-5
  MIXBETA_CELL = 0.5
  SET_INIT_STR = 2
  ADD_HESS_DIAG = 100.0

  RENORM_3TO2ND = 2
  RENORM_2TO1ST = 2
  RENORM_34TO1ST = 0
  STRAIN_IFC_DIR = strain_IFC
/

&displace
1 # cartesian
0.0 0.0 0.0
0.0 0.0 0.0
0.0 0.0 0.0
0.0 0.0 0.0
/

&strain
0.0 0.0 0.0
0.0 0.0 0.0
0.0 0.0 0.0
/

Do you have any clues on what's going wrong?

Besides that, I have another question: does the total Helmholtz energy (F_{total}) printed on .scph_thermo file, created with the cell relaxation option, include the pV (pressure * volume) term, or do we need to add it manually to investigate the Gibbs energy of the system?

[RicardoCecconello]

I "solved" it by setting MIXBETA_CELL = 0. However, in this case, the final strain (displacement gradient tensor u_{mu nu}) is always the same as the one from the input file, for every temperature (from 0 to 50 K). I also changed the &strain block, but this issue continued. It happens for other pressures as well.
Do you have suggestions?