Calc.  SED & PREDOM / Input data-file format

Data file structure: The chemical system

The input file consists of: 1) definition of the chemical system; 2) plot information; and 3) concentrations (ranges) for the chemical components.

The chemical system must be given as follows:

    Data to be entered:     Comments:


NA, NX, NF, SOLIDC,
IDENT(ia), (given for ia=1,NA)
IDENT(ix), LOGBTA(ix),
  (P(ia,ix), ia=1,NA), (for ix=1,NX)
IDENT(if), LOGBTA(if),
  (P(ia,if), ia=1,NA), (for if=1,NF)


where:

    NA = number of chemical components (the last SOLIDC components are assumed to be solid phases).
    NX = number of soluble complexes.
    NF = number of solid products.
    SOLIDC =  number of components which are solids (the last SOLIDC components are assumed to be solid phases).
    IDENT(i) = name for species i.
    LOGBTA(i) = logβ for species i, where β = global equilibrium constant of formation.
    P(j,i) = formula units (stoichiometric coefficient) for reaction i and component j.

Important: solids are given after soluble species. This means that the SOLIDC component names are given after soluble ones (for example, H+, Ca+2, CaCO3(s)), and solid products are given after any aqueous species. Examples: a system without solid phases, and a system with solids.

Although this appears complicated, it is quite simple:
  −  the first line specifies the number of components, dissolved species, and solids;
  −  the names of each component are given next;
  −  this is followed by one line for each species: the name, the equilibrium constant and the stoichiometry.