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[nathaniel.deskins@pnl.gov]

Hello all,

  I'm looking at the following gas-phase reaction. TiCl --> Ti + Cl.
The ground state for TiCl is a quintet (3 unpaired e-), Ti is a pentet(?) (4 
unpaired e-), while Cl is a doublet (1 unpaired e-). I've modeled this 
reaction with other planewave and gaussian codes. The energy for the reaction 
varies between 4.1-5.1 eV (depending on basis set and potential) while the 
Ti-Cl distance is near 2.22-2.23 angstroms. All this was with PBE XC 
functional. 

  When I've tried Abinit with the FHI GGA-PBE Troullier-Martins 
pseudopotentials I get strange results. My calculated energy is 6.58 eV while 
the Ti-Cl distance is 2.40 angstroms. This was for a cutoff of 15 hartree. 
For cutoff of 30 hartree the energy is 3.8 eV(?!) and the distance is 2.39 
angstroms.
 
  Either there is an issue with the pseudopotentials, or I'm doing something 
wrong. 

Below are my input files. Any help is appreciated. 

Thank you,
Aaron


ti.in
acell 25 25 25    # The keyword "acell" refers to the
ntypat 1          # There is only one type of atom
znucl 22           # The keyword "znucl" refers to the atomic number of the 
natom 1           # There are two atoms
typat 1          # They both are of type 1, that is, Hydrogen
xcart             # This keyword indicates that the location of the atoms
   0.0 0.0 0.0    # Triplet giving the cartesian coordinates of atom 1, in 
Bohr
ecut 15.0         # Maximal plane-wave kinetic energy cut-off, in Hartree
nkpt 1            # Only one k point is needed for isolated system,
nsppol 2
occopt 2
nband 8 8  
occ 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0   
spinat 0.0 0.0 4.0  # Initialisation of spin
nstep 50          # Maximal number of SCF cycles
toldfe 1.0d-6     # Will stop when, twice in a row, the difference 
diemac 2.0        # Although this is not mandatory, it is worth to


cl.in
acell 25 25 25    # The keyword "acell" refers to the
ntypat 1          # There is only one type of atom
znucl 17           # The keyword "znucl" refers to the atomic number of the 
natom 1           # There are two atoms
typat 1          # They both are of type 1, that is, Hydrogen
xcart             # This keyword indicates that the location of the atoms
   0.0 0.0 0.0    # Triplet giving the cartesian coordinates of atom 1, in 
Bohr
ecut 15.0         # Maximal plane-wave kinetic energy cut-off, in Hartree
nkpt 1            # Only one k point is needed for isolated system,
nsppol 2
occopt 2
nband 8 8  
occ 1 1 1 0 0 0 0 0 1 1 1 1 0 0 0 0   
spinat 0.0 0.0 1.0  # Initialisation of spin
nstep 50          # Maximal number of SCF cycles
toldfe 1.0d-6     # Will stop when, twice in a row, the difference 
diemac 2.0        # Although this is not mandatory, it is worth to
 

ticl.in
acell 25 25 25    # The keyword "acell" refers to the
ntypat 2          # There is only one type of atom
znucl 22 17          # The keyword "znucl" refers to the atomic number of the 
natom 2           # There are two atoms
typat 1 2         # They both are of type 1, that is, Hydrogen
xcart             # This keyword indicates that the location of the atoms
   0.0 0.0 0.0    # Triplet giving the cartesian coordinates of atom 1, in 
Bohr
   4.3 0 0 
ecut 30.0         # Maximal plane-wave kinetic energy cut-off, in Hartree
nkpt 1            # Only one k point is needed for isolated system,
nsppol 2
occopt 2
nband 12 12  
occ 1 1 1 1 1 1 1 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 
spinat 0.0 0.0 3.0  
       0.0 0.0 1.0
ionmov 2
tolmxf 5.0d-4
ntime 20
nstep 50          # Maximal number of SCF cycles
toldfe 1.0d-6     # Will stop when, twice in a row, the difference 
diemac 2.0        # Although this is not mandatory, it is worth to