How to represent 1s electron with ECP in the core-hole calculation?

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Dear all,

I trying to calculate chemical shifts in carbon 1s ionization energies following the ?SCF approach according to the protocol that was outlined in J. Chem. Theory Comput. 2011, 7, 4104–4114. So, I would like to do a calculation on CH4 from which one core electron has been ejected and there is now one electron left in the 1s orbital of the CH4(+) cation. The protocol calls for simulating this partially filled 1s core with an ECP (modified sbkjc_ecp). I got it working in another program but I am having trouble with NWChem.

I am not sure how to specify that the ECP-modeled core should have a single electron. When I use "nelec 1" in the ECP definition, the program stops with "The number of electrons 1 in the ECP does not accord with a known set of completely filled shells". Does this suggest that I can use ECPs in NWChem only to replace completely filled shells?

I have tried couple of things (charge keyword in the geometry input; set atomscf:z; uhf/rhf) with no luck. There is an example on how to do core-hole calculations with DFT without ECPs but I eventually want to run coupled cluster jobs. Any suggstions are most appreciated.

Example input:

title "Methane Core-Hole State w/ NWChem 6.5"
scratch_dir /work/nwchem
memory total 1000 mb
# These were suggested in CCL long time ago but did not seem to help me :(
set atomscf:z      1.0
set atomscf:tags_z C
# The core hole state of CH4 is singly charged
charge 1
# This comes from "Geometry_examples"
geometry units au
   c   0.0000000      0.0000000      0.0000000
   h   1.1828637      1.1828637      1.1828637
   symmetry group Td
basis spherical
  H library cc-pvtz
  C library cc-pvtz
# Trying to model the remaining singe electron by ECP
  C nelec   1
  C ul
  1      8.5646800             -0.4468550
  C S
  0      2.8149700              1.9292600
  2      8.1129600             14.8819900
# if singlet 
#   then "The number of electrons 1 in the ECP does not accord with a known set of completely filled shells"
# if doublet
#   then "scf: no. of closed-shell electrons is not even!                   1"  
task scf energy

--Kalju Dec 16th 7:58 am Local Time

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