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Dear friends,

i am currently trying to run gamma phonon calculation in 4h GaAs, so according the nlo tutorial i made following input

# Linear and nonlinear response calculation for AlAs
# Perturbations: electric fields & atomic displacements
# (M. Veithen, 21.4.2005)

#Definition of lattice parameters
#********************************
acell 7.3926115459E+00 7.3926115459E+00 2.4343461639E+01
rprim 5.0000000010E-01 -8.6602540370E-01 0.0000000000E+00
5.0000000010E-01 8.6602540370E-01 0.0000000000E+00
0.0000000000E+00 0.0000000000E+00 1.0000000000E+00

#Definition of atomic positions and types
#*************************************
natom 8
ntypat 2
znucl 31 33
typat 4*1 4*2
xred -6.3633415397E-09 1.5233758324E-07 1.8680818754E-01
-2.1818360876E-07 -1.9010575268E-08 6.8680815738E-01
3.3333331861E-01 6.6666684149E-01 4.3721796994E-01
6.6666650478E-01 3.3333332746E-01 9.3721789265E-01
-1.5967159161E-07 -5.1799357254E-10 3.6262574184E-04
-2.7297424114E-08 1.7058147241E-07 5.0036265620E-01
3.3333332814E-01 6.6666681624E-01 2.4961129047E-01
6.6666645999E-01 3.3333331142E-01 7.4961122008E-01
ixc 3

#Parameters of the SCF cycles
#****************************
iscf 5
nstep 1200

#Plane wave basis and k-point grid
#*********************************
ecut 15
ecutsm 0.5
dilatmx 1.05
ngkpt 8 8 8
nshiftk 1
shiftk 0 0 0.5

ndtset 5 jdtset 1 2 3 4 5

#DATASET1 : scf calculation: GS WF in the BZ
#********************************************
prtden1 1
kptopt1 1
toldfe1 1.0d-12

#DATASET2 : non scf calculation: GS WF in the whole BZ
#*****************************************************
getden2 1
kptopt2 2
iscf2 -2
getwfk2 1
tolwfr2 1.0d-22
nband2 17


#DATASET3 : ddk on the MP grid of k-points
#*****************************************
getwfk3 2
rfdir3 1 1 1
rfelfd3 2
tolwfr3 1.0d-22
nband3 17
kptopt3 2

#DATASET4 : ddE on the MP grid of k-points
#*****************************************
prtden4 1
getwfk4 2
getddk4 3
rfdir4 1 1 1
rfphon4 1
rfatpol4 1 2
tolvrs4 1.0d-12
rfelfd4 3
nband4 17
kptopt4 2
prepanl4 1

#DATASET5 : 3DTE calculation
#***************************
getden5 1
get1den5 4
getwfk5 2
get1wf5 4
nband5 17
kptopt5 2
optdriver5 5
rf1elfd5 1
rf1phon5 1
rf1atpol5 1 2
rf1dir5 1 1 1
rf2elfd5 1
rf2dir5 1 1 1
rf3elfd5 1
rf3dir5 1 1 1

nbdbuf 0

when code approaches to ds5 suddenly appears an error: initmv: ERROR -
In a non-linear response calculation, nband must be equal
to the number of valence bands.

and then it stops(
what does it mean? why it is imposible to take explicit value 17?
any ideas?

Well, it appears that your Ga pseudo has 3 electrons in valence and your As pseudo has 5, right? You have 4 Ga's and 4 As's in the unit cell, so 32 electrons or 16 filled bands in the insulating ground state. So the only way the code will work is if nband is 16, that's what the error means--nband must be set to exactly the number of filled bands (and presumably no metallic states allowed). For a simple phonon calculation, metallic states are allowed, but not for all responses.

thanx a lot, it helped;
sorry for repost;
all the best;