Example: Mössbauer spectroscopy: Ferrocene
******************************************

"Download Mossbauer.run"

   #! /bin/sh


   # By default in ADF the electron density at the nuclei is calculated, no input
   # key is required. The electron density at the nuclei could be used for the
   # interpretation of isomer shifts in Mossbauer spectroscopy. The absolute
   # electron density at a nucleus heavily depends on the accuracy of the basis set
   # in the core region of this nucleus, especially if relativistic effects are
   # included. Important is to use the same basis set, same exchange correlation
   # functional, same numerical accuracy, if electron densities at nuclei in
   # different molecules are compared. For the calculation of Mossbauer quadrupole
   # splittings the key QTENS is required For 57 Fe quadrupole splittings will be
   # written in units of mm/s, used in Mossbauer spectroscopy Example shows a
   # calculation on ferrocene with anon-relativistic, and two with a scalar
   # relativistic ZORA Hamiltonian using a different all electron basis set.

   # First a non-relativistic calculation.

   AMS_JOBNAME=NR $AMSBIN/ams <<eor
   System
     symmetrize Yes
     atoms
        Fe        0.000000    0.000000    0.000000
        C         1.215650    0.000000    1.600813
        C         0.375656   -1.156152    1.600813
        C        -0.983481   -0.714541    1.600813
        C        -0.983481    0.714541    1.600813
        C         0.375656    1.156152    1.600813
        C         1.215650    0.000000   -1.600813
        C         0.375656    1.156152   -1.600813
        C        -0.983481    0.714541   -1.600813
        C        -0.983481   -0.714541   -1.600813
        C         0.375656   -1.156152   -1.600813
        H         2.310827    0.000000    1.629796
        H         0.714085   -2.197727    1.629796
        H        -1.869498   -1.358270    1.629796
        H        -1.869498    1.358270    1.629796
        H         0.714085    2.197727    1.629796
        H         2.310827    0.000000   -1.629796
        H         0.714085    2.197727   -1.629796
        H        -1.869498    1.358270   -1.629796
        H        -1.869498   -1.358270   -1.629796
        H         0.714085   -2.197727   -1.629796
     end
   end

   Task SinglePoint

   Engine ADF
     title ferrocene
     exactdensity
     basis
       core none
       type TZP
     end
     numericalquality Good
     qtens
     xc
       gga blyp
     end
     Relativity
       Level None
     End
   EndEngine
   eor


   # Next the scalar relativistic ZORA calculations. ADF will also calculate the
   # quadrupole splittings including the small component density, also called SR
   # ZORA-4.


   AMS_JOBNAME=SR $AMSBIN/ams <<eor
   System
     symmetrize
     atoms
        FE        0.000000    0.000000    0.000000
        C         1.215650    0.000000    1.600813
        C         0.375656   -1.156152    1.600813
        C        -0.983481   -0.714541    1.600813
        C        -0.983481    0.714541    1.600813
        C         0.375656    1.156152    1.600813
        C         1.215650    0.000000   -1.600813
        C         0.375656    1.156152   -1.600813
        C        -0.983481    0.714541   -1.600813
        C        -0.983481   -0.714541   -1.600813
        C         0.375656   -1.156152   -1.600813
        H         2.310827    0.000000    1.629796
        H         0.714085   -2.197727    1.629796
        H        -1.869498   -1.358270    1.629796
        H        -1.869498    1.358270    1.629796
        H         0.714085    2.197727    1.629796
        H         2.310827    0.000000   -1.629796
        H         0.714085    2.197727   -1.629796
        H        -1.869498    1.358270   -1.629796
        H        -1.869498   -1.358270   -1.629796
        H         0.714085   -2.197727   -1.629796
     end
   end

   Task SinglePoint

   Engine ADF
     title ferrocene
     exactdensity
     basis
       core none
       type TZP
     end
     numericalquality Good
     qtens
     relativity
       level scalar
       formalism ZORA
     end
     xc
       gga blyp
     end
   EndEngine
   eor


   # Next a scalar relativistic calculation is performed with a much larger basis
   # set (QZ4P) in the core region. Changing the basis set will have a large effect
   # on the electron density at the nucleus and a noticeable effect on the
   # calculated quadrupole splittings.


   AMS_JOBNAME=SR_QZ4P $AMSBIN/ams <<eor
   System
     symmetrize
     atoms
        FE        0.000000    0.000000    0.000000
        C         1.215650    0.000000    1.600813
        C         0.375656   -1.156152    1.600813
        C        -0.983481   -0.714541    1.600813
        C        -0.983481    0.714541    1.600813
        C         0.375656    1.156152    1.600813
        C         1.215650    0.000000   -1.600813
        C         0.375656    1.156152   -1.600813
        C        -0.983481    0.714541   -1.600813
        C        -0.983481   -0.714541   -1.600813
        C         0.375656   -1.156152   -1.600813
        H         2.310827    0.000000    1.629796
        H         0.714085   -2.197727    1.629796
        H        -1.869498   -1.358270    1.629796
        H        -1.869498    1.358270    1.629796
        H         0.714085    2.197727    1.629796
        H         2.310827    0.000000   -1.629796
        H         0.714085    2.197727   -1.629796
        H        -1.869498    1.358270   -1.629796
        H        -1.869498   -1.358270   -1.629796
        H         0.714085   -2.197727   -1.629796
     end
   end

   Task SinglePoint

   Engine ADF
     title ferrocene
     exactdensity
     basis
       core none
       type QZ4P
     end
     numericalquality Good
     qtens
     relativity
       level scalar
       formalism ZORA
     end
     xc
       gga blyp
     end
   EndEngine
   eor
