#!/bin/sh

# Example restricted open shell Kohn-Sham (ROKS, ROSCF) for SF.

# The method implemented in ADF needs integer occupation numbers,
# and a positive spin polarization.
# In this case one can not use full C(lin) symmetry, since one of
# the orbitals in one of the degenerate representation might not
# be fully occupied or zero.
# If one would use C(lin) one of the orbitals in the degenerate 
# irrep Pi would have 1 beta electron.
# This looks like an integer number, however, 1 beta electron in Pi
# effectively would lead to a fractional 0.5 electron in Pi:x and
# 0.5 electron in Pi:y beta orbital.
# Since this method needs integer occupations, a lower symmetry is
# used, in this case C(2v).
# Note that in this case one needs to use the key Occupations IntegerAufbau
# or explicit integer occupation numbers with the key IrrepOccupations, 
# otherwise one could still end up with fractional occupation numbers.

"$AMSBIN/ams" << eor
Task SinglePoint
System
    Atoms
        S  0.0000 0.0000 0.0000
        F  0.0000 0.0000 1.6000
    End
End

Engine ADF
    Basis
        Type TZ2P
        Core None
    End
    SpinPolarization 1
    XC
        Hybrid B3LYP
    End
    Scf
        ROSCF
        End
    End
    symmetry C(2v)
    Unrestricted Yes
    Occupations IntegerAufbau
    NumericalQuality Good
    IrrepOccupations
       A1 7 // 7
       B1 3 // 3
       B2 3 // 2
    End
EndEngine
eor