Table of Contents

About Muffin-Tin Potential Crystal Input File XT.DAT

We shall go over what goes into defining the lattice and program controls. This file needs to be made in two versions. One for the calculation of the scattering phase shifts and the other for the calculation of the EXAFS matrix elements.

I. Look at the input as defined by READ lines.

      READ(5,100)TITLE
      READ(5,101)SPA,ANG
      READ(5,101)((RC(I,J),I=1,3),J=1,3)
      READ(5,218)IPX,IREL
      READ(5,102)NR
      JJ=0
      DO 4 IR=1,NR
          READ(5,100)(NAME(I,IR),I=1,2)
          READ(5,103)NRR(IR),Z(IR),ZC(IR),RMT(IR)
          DO 4 J=1,N
              JJ=JJ+1
              READ(5,101)RK(1,JJ),RK(2,JJ),RK(3,JJ)
   4  CONTINUE
      READ(5,103)NHM,ALPHA,ATDIAM,FLOMT,EXPRES,RMTZ
  14  DO 18 IR=1,NR
          READ(5,218)L,NE,E,DE
          IF(IPX.NE.1.AND.L.LT.0)GOTO 18
C  IF IPX=1 RONUC IS CALLED TO CALCULATE MATRIX ELEMENTS FOR X-RAY ABSORPTION
 902      CALL RONUC(Z(IR),NGRID,ATL,XM,WM,RMT(IR),E,DE,NE,L,IR)
  18  CONTINUE

 100  FORMAT(9A8)
 101  FORMAT(3F8.4)
 102  FORMAT(I4)
 103  FORMAT(I4,5F8.4)
 218  FORMAT(2I4,2F8.4)

      SUBROUTINE RONUC(Z,NM,VM,XM,WM,RM,E1,DE,NJE,LI,IR)
      READ(5,10) NCORE,ECORE

  10  FORMAT(I4,F11.5)





line01 [TITLE] line02 [SPA] [ANG] line03 { [RC(1,1)] [RC(2,1)] [RC(3,1)] for unit cell axis 1 } line03.1 { [RC(1,2)] [RC(2,2)] [RC(3,2)] for unit cell axis 2 } line03.2 { [RC(1,3)] [RC(2,3)] [RC(3,3)] for unit cell axis 3 } line04 [IPX] [IREL] line05 [NR] line06 { [NAME(1)] for atom 1, emitter atom type } line07 { [NRR(1)] [Z(1)] [ZC(1)] [RMT(1)] } line08 { { [RK(1,1)] [RK(2,1)] [RK(3,1)] for position 1 } } line08.1 { { [RK(1,2)] [RK(2,2)] [RK(3,2)] for position 2 } } line08.2 { { ... } } line09 { [NAME(2)] for atom 2 } line10 { [NRR(2)] [Z(2)] [ZC(2)] [RMT(2)] } line11 { { [RK(1,3)] [RK(2,3)] [RK(3,3)] for position NRR(1)+1 } } line11.1 { { ... } } line12 [NHM] [ALPHA] [ATDIAM] [FLOMT] [EXPRES] [RMTZ] line13A { [L] [NE] [E] [DE] for atom 1 phase shift } line13A.1 { [L] [NE] [E] [DE] for atom 2 phase shift } line13A.2 { ... } line13B { [L] [NE] [E] [DE] for atom 1 EXAFS matrix } line14B { [NCORE] [ECORE] for atom 1 EXAFS matrix } line13B.1 { [L] [NE] [E] [DE] for atom 2 EXAFS matrix } line14B.1 { -1 0.0 for atom 2 EXAFS matrix } line13B.2 { ... } line14B.2 { ... }

II. Discussion of the details of each input line

Using Zinc Centered ZincOxide for Example Input
Wyckoff, R. W. G., Crystal Structures, Interscience Publishers, NY, 1965, defines the wurtzite structure for ZnO as a two-molecule hexagonal unit with atoms arranged in the positions:

  1. line 01, Title :

  2. TITLE - A descriptive name for the input file
    Example:  ZnO:ZnO Wurtzite STRUCTURE
  3. line 02, Unit Cell Parameters :
  4. Example:    6.1407  1.
  5. lines 03, Axes of the Unit Cell :

  6. RC(1,J),RC(2,J),RC(3,J) - X,Y,Z coordinates of the J'th axis of the unit cell, in units of SPA. These describe the vectors of the unit cell axes in cartesian coordinates.
    Example:    0.8660 -0.5000  0.0000
                0.0000  1.0000  0.0000
                0.0000  0.0000  1.6024
                for ZnO in a hexagonal close packed lattice with c/a = 1.6024.
  7. line 04, Results Control Parameters :
  8. Example:     0   0
                 for a non-L.S calculation of phase shift
  9. line 05, Inequivalent Atoms :

  10. NR - how many unique atoms exist in the lattice and have data to be read in.
    Example:     2
  11. line 06, Title of Atom 1, the Emitter Atom Type :

  12. NAME(1) - title of atom 1. This atom type must contain the "excited" atom, which is assumed to be the origin of the lattice and scattering events.
    Example:  ZINC
  13. line 07, Atom 1 Information :
  14. Example:     2 30.0000  0.0000  2.2916
  15. lines 08, Positions of Atoms of Type 1 :

  16. RK(1,n),RK(2,n),RK(3,n) - coordinates of the n'th atom in the unit cell for atoms of type 1, in units of SPA. If, from line02, ANG = 0, the coordinates are cartesian X,Y,Z; if ANG = 1, the coordinates are given in units of the vectors described.
    Example:    0.0000  0.0000  0.0000
                0.3333  0.6667  0.5000
                for the emitter at the origin and another 
                atom at 1/3a,2/3a,1/2c of the hcp unit cell.
  17. line 09, Title of Atom 2 :

  18. The title of atom type 2.
    Example:  OXYGEN
  19. line 10, Atom 2 Information :

  20. The same as line07, but for atom type 2.
    Example:     2  8.0000  0.0000  2.2916
  21. line 11, Positions of Atoms of Type 2 :

  22. The same as line08, but for atom type 2.
    Example:    0.0000  0.0000  0.3450
                0.3333  0.6667  0.8450
  23. line 12, Muffin-Tin Control Parameters :
  24. Example:    16  0.7256  3.3947  0.2341  1.0000  0.0000
  25. lines 13, Description of the State of Each Atomic Type :

  26. There are two cases described here: case A for scattering phase shifts, case B for EXAFS matrix elements. These can not be included in the same input file although both are described here. Two separate input files must be made, one for each. Which input is appropriate is determined by line04, IPX.
    Note: It is certainly convenient (I don't know if it is necessary) for the energy range and grid used for the two results to be the same.
    1. Scattering Phase Shifts

    2. There should be one line for each unique atom type, with the lines listed in the same order as the atom types were given in.
      Example:     3 200  0.2500  0.0085
                   3 200  0.2500  0.0085
                   Note: Usually l=3 is the max. angular momentum state
                   necessary.  If in doubt, run for l=4 and check that
                   the phase shifts are negligible (< 1E-02 rad, say).
    3. EXAFS Matrix Elements

    4. This line need only have correct values for the first atom type, the emitter. Being the "excited" atom, it is the atom that creates the matrix elements.
      Example:     1 200  0.2500  0.0085
                   3  -36.39756
                   1 200  0.0000  0.0000
                  -1   -0.00000
                   Note: These are lines13B AND 14B.  The emitter atom
                   type is the ZINC atom 2p state.
  27. lines 14B, Additional Description of the State of Each Atomic Type for EXAFS Matrix Elements :

  28. These lines are only necessary for IPX = 1, output EXAFS Matrix Elements for the emitter atom.
    1. not used
    2. EXAFS Matrix Elements

    3. As for line 13B, this line need only have correct values for the first atom type, the emitter.
      Example:  See lines 13,B above.
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Created: April 8, 1999 ---- Last Updated: April 12, 1999
By Mark D. Pauli