[QE-users] Question about Ti L2/L3-edge XSpectra calculations with Ti half-core-hole GIPAW pseudopotential
qin xixi
xixi.qin at hotmail.com
Mon May 11 23:42:25 CEST 2026
Dear XSpectra and QE developers and users,
I would like to ask a question about Ti L2/L3-edge calculations using a scalar-relativistic Ti half-core-hole pseudopotential (please see my ld1.x, pw.x and xspectra.x inputs below).
I’m testing this on a bulk anatase system with 8 equivalent Ti-sites, and replacing them one-by-one with the Ti half-core-hole pseudopotential leads to the same PDOS projected onto that site as expected. Total energies are numerically identical, too. When I run xspectra on top of this however, I get x/y/z/-averaged XAS that seem to be shifted quite significantly wrt. each other (see figure), rather than identical XAS I would expect from symmetrically equivalent core-excited sites.
[Image] [Image]
When I use the same Ti.wfc wavefunction file but with a Ti pseudopotential without core hole, the resulting ‘XAS’ do look identical for symmetrically equivalent sites. I am wondering if it’s a GIPAW reconstruction issue with my pseudopotential.
I also tested the Cu2O and CuO structures with the half-core-hole pseudopotentials from the tutorial, and those work fine yielding same XAS for equivalent sites.
I have attached the input file for generating the Ti pseudopotential, the Ti pseudopotential itself, the xspectra.x and pw.x inputs and the calculation results.
I would greatly appreciate any help or suggestions. If you can share me the input file for Cu half core GIPAW pseudopotential included with the xspectra examples, that could be helpful to see if I’m missing something wrong for the Ti-case.
Best regards,
Xixi Qin
Postdoctoral Scholar, SLAC
Ld1.x input:
For neutral Ti pp.
&input
title = 'Ti'
prefix = 'ti'
verbosity = 'high'
zed = 22
config = '[Ar] 4s2 4p0 3d2 4d0'
dft = 'pbe'
rel = 1
iswitch = 3
beta = 0.2
xmin = -8.0, dx = 0.01
nld = 4, rlderiv = 2.3, eminld = -5.0, emaxld = 5.0, deld = 0.002
/
&inputp
pseudotype = 3
lloc = -1
rcloc = 1.10
tm = .true.
nlcc = .true.
new_core_ps = .true.
rcore = 0.7
file_core = 'Ti.core'
file_pseudopw = 'Ti.pbe-rrkjus-semi-gipaw-ct-dc.UPF'
lgipaw_reconstruction = .true.
author = 'Christian Tantardini & Davide Ceresoli'
/
6
3S 1 0 2.0 0.00 0.90 1.10
4S 2 0 2.0 0.00 0.90 1.10
3P 2 1 6.0 0.00 0.90 1.10
4P 3 1 0.0 0.00 0.90 1.10
3D 3 2 2.0 0.00 0.90 1.10
3D 3 2 -1.0 0.50 0.90 1.10
&test
ecutmin = 40
ecutmax = 90
decut = 10
/
6
3S 1 0 2.0 0.00 0.90 1.10
4S 2 0 2.0 0.00 0.90 1.10
3P 2 1 6.0 0.00 0.90 1.10
4P 3 1 0.0 0.00 0.90 1.10
3D 3 2 2.0 0.00 0.90 1.10
4D 4 2 -1.0 0.50 0.90 1.10
For half core hole Ti pp.
&input
title = 'Ti'
prefix = 'ti'
verbosity = 'high'
zed = 22
! config = '[Ar] 4s2 4p0 3d2 4d0'
config='1s2 2s2 2p5.5 3s2 3p6 4s2 4p0 3d2 4d0',
dft = 'pbe'
rel = 1
iswitch = 3
beta = 0.2
xmin = -8.0, dx = 0.01
nld = 4, rlderiv = 2.3, eminld = -5.0, emaxld = 5.0, deld = 0.002
/
&inputp
pseudotype = 3
lloc = -1
rcloc = 1.10
tm = .true.
nlcc = .true.
new_core_ps = .true.
rcore = 0.7
file_core = 'Ti.core',
zval = 12.5,
file_pseudopw = 'Ti.hch.pbe-rrkjus-semi-gipaw-ct-dc.UPF'
lgipaw_reconstruction = .true.
author = 'Christian Tantardini & Davide Ceresoli'
/
6
3S 1 0 2.0 0.00 0.90 1.10
4S 2 0 2.0 0.00 0.90 1.10
3P 2 1 6.0 0.00 0.90 1.10
4P 3 1 0.0 0.00 0.90 1.10
3D 3 2 2.0 0.00 0.90 1.10
3D 3 2 -1.0 0.50 0.90 1.10
&test
ecutmin = 40
ecutmax = 90
decut = 10
/
6
3S 1 0 2.0 0.00 0.90 1.10
4S 2 0 2.0 0.00 0.90 1.10
3P 2 1 6.0 0.00 0.90 1.10
4P 3 1 0.0 0.00 0.90 1.10
3D 3 2 2.0 0.00 0.90 1.10
Input file for pw.x
&control
calculation = 'scf',
prefix = 'tio2',
pseudo_dir = '../psp',
outdir = 'out',
verbosity='high',
/
&system
ibrav = 0,
nat = 48,
ntyp = 3,
ecutwfc = 60.000,
ecutrho = 480.000,
input_dft = 'PBE',
nspin = 1,
nosym = .false.,
noinv = .false.,
tot_charge = 0.500000000000,
occupations="smearing",
smearing='fd',
degauss=0.005,
starting_magnetization(1) = 0.0
starting_magnetization(2) = 0.0
starting_magnetization(3) = 0.0
!tot_magnetization = 0.000000,
/
&electrons
conv_thr = 1.0d-8,
mixing_beta = 0.20,
/
ATOMIC_SPECIES
O 15.999400 O_PBE_USPP.UPF
Ti 47.867000 Ti.pbe-rrkjus-semi-gipaw-ct-dc.UPF
Tih 47.867000 Ti.hch.pbe-rrkjus-semi-gipaw-ct-dc.UPF
CELL_PARAMETERS angstrom
7.5650792122 0.0000000000 0.0000000000
0.0000000000 7.5650792122 0.0000000000
0.0000000000 0.0000000000 9.6150217056
ATOMIC_POSITIONS angstrom
Tih 0.000000000 0.000000000 0.000000000
Ti 1.891269803 1.891269803 4.807510853
Ti 0.000000000 1.891269803 2.403755426
Ti 1.891269803 0.000000000 7.211266279
Ti 0.000000000 3.782539606 0.000000000
Ti 1.891269803 5.673809409 4.807510853
Ti 3.782539606 1.891269803 2.403755426
Ti 5.673809409 0.000000000 7.211266279
Ti 1.891269803 3.782539606 7.211266279
Ti 0.000000000 5.673809409 2.403755426
Ti 5.673809409 1.891269803 4.807510853
Ti 3.782539606 0.000000000 0.000000000
Ti 3.782539606 3.782539606 0.000000000
Ti 5.673809409 5.673809409 4.807510853
Ti 3.782539606 5.673809409 2.403755426
Ti 5.673809409 3.782539606 7.211266279
O 0.000000000 0.000000000 1.991772066
O 1.891269803 1.891269803 6.799283062
O 0.000000000 1.891269803 4.395527636
O 1.891269803 0.000000000 9.203038488
O 1.891269803 0.000000000 5.219494070
O 0.000000000 1.891269803 0.411983360
O 1.891269803 1.891269803 2.815738644
O 0.000000000 0.000000000 7.623249496
O 0.000000000 3.782539606 1.991772066
O 1.891269803 5.673809409 6.799283062
O 3.782539606 1.891269803 4.395527636
O 5.673809409 0.000000000 9.203038488
O 1.891269803 3.782539606 5.219494070
O 0.000000000 5.673809409 0.411983360
O 5.673809409 1.891269803 2.815738644
O 3.782539606 0.000000000 7.623249496
O 3.782539606 0.000000000 1.991772066
O 5.673809409 1.891269803 6.799283062
O 0.000000000 5.673809409 4.395527636
O 1.891269803 3.782539606 9.203038488
O 5.673809409 0.000000000 5.219494070
O 3.782539606 1.891269803 0.411983360
O 1.891269803 5.673809409 2.815738644
O 0.000000000 3.782539606 7.623249496
O 3.782539606 3.782539606 1.991772066
O 5.673809409 5.673809409 6.799283062
O 3.782539606 5.673809409 4.395527636
O 5.673809409 3.782539606 9.203038488
O 5.673809409 3.782539606 5.219494070
O 3.782539606 5.673809409 0.411983360
O 5.673809409 5.673809409 2.815738644
O 3.782539606 3.782539606 7.623249496
K_POINTS automatic
5 5 4 0 0 0
HUBBARD {ortho-atomic}
U Ti-3d 4
U Tih-3d 4
For xspectra.x input:
&input_xspectra
calculation='xanes_dipole',
prefix='tio2',
edge='L2',
outdir='./out',
xniter=2000,
xcheck_conv=50,
xkvec(1)=1.0,
xkvec(2)=0.0,
xkvec(3)=0.0,
xepsilon(1)=1.0,
xepsilon(2)=0.0,
xepsilon(3)=0.0,
xonly_plot = .false.,
xe0 = 7.0,
xiabs=3,
lplus=.true.,
x_save_file='tio2_oh.ex.xspectra.sav',
xerror=0.001,
/
&plot
xnepoint=1800,
xgamma=0.5,
xemin=-30.0,
xemax=60.0,
terminator=.true.,
cut_occ_states=.false.,
xanes_file='xanes.ex.dat'
/
&pseudos
filecore='Ti.wfc',
r_paw(1)=1.5,
/
&cut_occ
/
5 5 4 0 0 0
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