Directives

After the header lines, AOMX expects directives, each consisting of a directive name (which is always composed of three capital letters) followed by data, further keywords or the names of user defined variables. Directives may have line structure or block structure; it is important that those having block structure must be terminated by a blank line. The following directives are known to AOMX:

• VAR: Definition of variables. The additional options OPT and STA induce optimization of some of the variables by fitting them to experimental data resp. an error propagation calculation (statistical analysis of the energy hypersurface in parameter space).
• XYZ or TPP (or RTP): Input of the angular geometry of the complex in form of cartesian coordinates or Euler angles (or polar coordinates).
• AOM: Input of AOM parameters
• CON: Definition of connected ligands
• VEE: Input of electron repulsion parameters (Racah parameters) and orbital reduction factors
• HSO: Input of the spin-orbit coupling parameter
• HMG: Input of magnetic field parameters
• EXP: Input of experimental data
• CTL: Input of special options for printout or parameter optimization
• RUN: Start a run with actual input data

Normally, the sequence of directives is not important. But there are exceptions that are coherent with the fact that AOMX scans the input file only once and, while doing so, immediately evaluates the directives it encounters:

1. No variable may be used prior to its definition.
2. The CON directive which denotes ligand connectivity may occur only if coordinates and AOM parameters are already defined.
3. Some of the options of the CTL directive have different effects in calculations with and without optimization. Therefore, CTL should not occur before VAR.

• VAR  Definition and variation of variables (block)
• XYZ  Cartesian coordinates (block)
• TPP  Euler angles (block)
• RTP  Polar coordinates (block)
• AOM  AOM parameters (block)
• CON  Connected ligands (block)
• VEE  Electron repulsion parameters (line)
• HSO  Spin-orbit parameters (line)
• HMG  Magnetic field parameters (line)
• TRE  Trees parameter (line)
• EXP  Experimental data (block)
  • Assignment with symmetry.
  • Assignment without symmetry.
• BAS  Basis set restriction (block)
  • Minimal spin multiplicity.
  • Minimal and maximal orbital occupations.
• CTL  Control options (line)
• RUN  Start a run (line)