Let us illustrate the calculation for the absolute binding energies of core levels in bulk by introducing TiC bulk as an example. The initial state calculation can be performed by
% mpirun np 112 ./openmx TiC216.dat  tee TiC216.stdwhere any special keyword is not specified, but the spinpolarized calculation is performed with 'scf.SpinPolarization=on'. The input file 'TiC216.dat' is available in the directory 'work'. The final state calculation can be performed by
% mpirun np 112 ./openmx TiC216CH3.dat  tee TiC216CH3.stdThe input file 'TiC216CH3.dat' is available in the directory 'work'. In the input file the atomic species are defined by
<Definition.of.Atomic.Species Ti Ti7.0s3p2d2 Ti_PBE13 C C6.0_1ss3p2d1 C_PBE17_1s C1 C6.0_1s_CHs3p2d1 C_PBE17_1s Definition.of.Atomic.Species>and the species of 'C1' is allocated for atom 5 as
Atoms.Number 216 Atoms.SpeciesAndCoordinates.Unit Ang # AngAU <Atoms.SpeciesAndCoordinates 1 Ti 0.000000000000 0.000000000000 0.000000000000 6.0 6.0 2 Ti 2.163500000000 2.163500000000 0.000000000000 6.0 6.0 3 Ti 0.000000000000 2.163500000000 2.163500000000 6.0 6.0 4 Ti 2.163500000000 0.000000000000 2.163500000000 6.0 6.0 5 C1 2.163500000000 0.000000000000 0.000000000000 3.0 3.0 6 C 0.000000000000 2.163500000000 0.000000000000 3.0 3.0 7 C 0.000000000000 0.000000000000 2.163500000000 3.0 3.0 8 C 2.163500000000 2.163500000000 2.163500000000 3.0 3.0 .... .. Atoms.SpeciesAndCoordinates>Then, a core hole is created for the state on atom 5 by
scf.restart on scf.restart.filename TiC216 scf.coulomb.cutoff on scf.core.hole on scf.system.charge 0.0 # default=0.0 <core.hole.state 5 s 1 core.hole.state>The Hartree potential in the final state calculation consists of two contributions [88]: periodic part and nonperiodic part as
(15) 
After finishing the calculations for the initial and final states, you may obtain the total energies from the out files as
Initial state: 10499.900104007471 (Hartree) Final state: 10489.553360141708 (Hartree)

As an example of gapped systems, let us introduce calculations for bulk silicon. One can perform the initial and final state calculations as
% mpirun np 256 ./openmx Si4SOI.dat  tee Si4SOI.std % mpirun np 256 ./openmx Si4CHSOI1.dat  tee Si4CHSOI1.std % mpirun np 256 ./openmx Si4CHSOI6.dat  tee Si4CHSOI6.stdThe input file of 'Si4SOI.dat' is for the initial state calculation, while 'Si4CHSOI1.dat' and 'Si4CHSOI6.dat' are for the final state calculations with a core hole for the state on Si atom specified by and , respectively. To take account of the spinorbit interaction in the state on the Si atom the noncollinear calculations are performed by specifying the following keywords:
scf.SpinPolarization nc # OnOffNC scf.SpinOrbit.Coupling on # OnOff, default=off
After finishing the calculations for the initial and final states, you may obtain the total energies from the out files as
Initial state: 34820.483255130872 (Hartree) Final state for SOI1: 34816.628201335407 (Hartree) Final state for SOI6: 34816.601864921540 (Hartree)and the chemical potential can be obtained from the initial state calculation. Then, using Eq. (13) the binding energies for SOI1 and SOI6 are found to be
The other examples of calculations and input files used for the calculations can be found in the website: https://tozaki.issp.utokyo.ac.jp/vps_pao_core2019/. Also, applications of the method for silicene, borophene, and single Pt atoms dispersed on graphene can be found in Refs. [93,94,95].