Dear Matthieu and others,

Thanks very much for this discussion which is related to the question of how one might efficiently calculate phonons for large unit cell materials. I too tried to use prtwf 0 but found that the very large _1WFx files are still being written. (By the way – prt1wf does not seem to exist for version 9.8.1 which was released yesterday (1/2/2023).) Most likely I am making a very silly mistake. For example, the following *abi file for NaCl writes out all _1WFx files while my intent was to only write it for datasets 4-10. Thanks in advance for any suggestions. Natalie Holzwarth

-----*abi file for NaCl phonons----

#
Crystalline NaCl : computation of the phonon spectrum

ndtset 10

#Set 1 : ground state self-consistency

getwfk1 0 # Cancel default

kptopt1 1 # Automatic generation of k points, taking

# into account the symmetry

nqpt1 0 # Cancel default

tolvrs1 1.0d-18 # SCF stopping criterion (modify default)

rfphon1 0 # Cancel default

prtwf1 1

#Q vectors for all datasets

#Complete set of symmetry-inequivalent qpt chosen to be commensurate

#
with kpt mesh so that only one set of GS wave functions is needed.

#Generated automatically by running GS calculation with kptopt=1,

#
nshift=0, shiftk=0 0 0 (to include gamma) and taking output kpt set

#
file as qpt set. Set nstep=1 so only one iteration runs.

```
nqpt 1 # One qpt for each dataset (only 0 or 1 allowed)
# This is the default for all datasets and must
# be explicitly turned off for dataset 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
```

#Set 2 : Response function calculation of d/dk wave function

```
iscf2 -3 # Need this non-self-consistent option for d/dk
```

kptopt2 2 # Modify default to use time-reversal symmetry

rfphon2 0 # Cancel default

rfelfd2 2 # Calculate d/dk wave function only

tolwfr2 1.0d-22 # Use wave function residual criterion instead

prtwf2 1

#Set 3 : Response function calculation of Q=0 phonons and electric field pert.

getddk3 2 # d/dk wave functions from last dataset

kptopt3 2 # Modify default to use time-reversal symmetry

rfelfd3 3 # Electric-field perturbation response only

#Sets 4-10 : Finite-wave-vector phonon calculations (defaults for all datasets)

getwfk 1 # Use GS wave functions from dataset1

kptopt 3 # Need full k-point set for finite-Q response

rfphon 1 # Do phonon response

rfatpol 1 2 # Treat displacements of all atoms

rfdir 1 1 1 # Do all directions (symmetry will be used)

tolvrs 1.0d-8 # This default is active for sets 3-10

prtwf 0 # donot save wfn??

prtpot 0 # donot save pot??

prtden 0 # donot save den??

#######################################################################

#Common input variables

paral_kgb 1

autoparal 1

timopt -2

#Definition of the unit cell

acell 3*10.3340116399024

rprim 0.5 0.5 0.0

0.0 0.5 0.5

0.5 0.0 0.5

#Definition of the atom types

ntypat 2

znucl 11 17

#Definition of the atoms

natom 2

typat 1 2

xred

0.0 0.0 0.0

0.5 0.5 0.5

#Definition of the planewave basis set

ecut 35.0 # Maximal kinetic energy cut-off, in Hartree

pawecutdg 35.0

usexcnhat 0

pawxcdev 0

chksymtnons 0

#Definition of the k-point grid

ngkpt 8 8 8

nshiftk 4

shiftk 0.5 0.5 0.5

0.5 0.0 0.0

0.0 0.5 0.0

0.0 0.0 0.5

#Definition of the SCF procedure

nstep 120 # Maximal number of SCF cycles

nband 8

diemac 9.0 # Although this is not mandatory, it is worth to

# precondition the SCF cycle. The model dielectric

# function used as the standard preconditioner

# is described in the “dielng” input variable section

#
add to conserve old < 6.7.2 behavior for calculating forces at each SCF step

optforces 1

##
pp_dirpath “/deac/phy/natalieGrp/natalie/wfurc9/EL6/rc9/PAWatoms/poscorenhatPBESOL/libxc/”

pseudos “Na/Na.GGA_X_PBE_SOL+GGA_C_PBE_SOL-paw.xml, Cl/Cl.GGA_X_PBE_SOL+GGA_C_PBE_SOL-paw.xml”