Structure Format

Essential Parts:

•   Metric Tensor: [Å, deg]
  3x3 double precision real matrix as G, header needs to specify the sequence of matrix
  

•   Symmetry of the average structure
  32 Characters that have the space group symbol
  

•   Number of unit cells in a, b, c direction
  3 unsigned integer
  

•   number of atoms (NA) in file
  1 unsigned integer
  

•   List of atom types that are present in the structure, including atomic number, charge and isotope
  Four columns, NA lines:
  o   atom type: 2 characters
  o   Atomic number: unsigned integer number
  o   Charge: signed integer number
  o   Isotope: unsigned integer number
  

•   Atom type and atomic coordinates: this should be a table with 9 columns and NA lines
  o   1st column: Atom id, 1 integer
  o   2nd column: Atom type, 1 integer (identifies the type according to number in list of atom types)
  o   3rd – 5th column: x,y,z coordinates in the supercell from 0-1, 3 double precision real numbers
  o   6th – 9th column: unit cell identifier, coordinates of the atoms unit cell in the supercell and site in the average unit cell, 4 integers
  

•   Flags: Listed as flag name, data type Boolean, brackets as explanation what does
  o   Super structure
  o   Asymmetric unit (only asymmetric unit is stored)
  o   Are periodic boundary conditions sensible
  o   Homogeneity (Is it sensible to collapse the structure in one unit-cell, should be no for structures with drastically different parts, e.g. domains. If this is yes then the average crystallographic cell needs to be stored)
  

Metadata: o Timestamp o Software: Generated by software including its version version

Optional Parts:

•   If possible can we kind of attach a script/macro that created the structure?, e.g. containing Interaction Hamiltonian used in the generation of the structure
  

•   Average structure this should be a table with  12 columns
  

  o 1st column: Atom type, 1 integer (identifies the type according to number in list of atom types o 2nd – 4th column: x,y,z coordinates, 3 double precision real number o 5th column: average occupancy of the atom type in 1st column on this site, 1 double precision real number o 6th column: Uiso, 1 double precision real number o 7th – 12th column: u_ij, 6 double precision real numbers

•   Molecular identity
  

  o 2 integers, 1st labelling type of molecule, 2nd labelling number of molecule

•   Magnetic spin
  

  o 3 real numbers, components of spin vectors along crystal axis

•   Property flags: List of NA integers TO BE EXTENDED BY DISCUS AND RMC WITH THEIR FLAGS
  

  o Surface atom o Domain number