General Presentation

The ToPMod package enables the calculation of the ELF function on a 3-dimensional grid, the assignment of the basins and the calculation of the basin populations and of their variance. It uses wave functions written in a wfn file which is available as output file generated by Gaussian92/94/98/03 and GAMESS ab initio softwares. The modules are written in FORTRAN 90 in order to enable dynamic memory allocation.

In order to carry out a standard ELF analysis three programs have to be run in the following order:

• grid90: calculates ELF on a 3-D grid parallel to the standard axis defined in the MO calculation (this allows to exploit the factorization of the gaussian functions),
• bas90: assigns the grid points to basins,
• pop90: calculates the basin populations and variances.

The other modules do the following tasks:

• top_sym: exploits abelian symmetry operations,
• search90: localizes the critical points of the ELF gradient field,
• mod_wfn: enables to remove atoms in the case of large systems in order to focuss the calculation on the region of interest,
• sym_wfn: symmetrizes the wfn file for ²Π states of linear molecules
• bas_to_syn: assigns basin types from bas.sbf file,
• sbf_to_cube: converts sbf files to cube files for Molekel,
• sbf_to_am: converts sbf files to iam files for Amira,
• wfn_to_line: generates a wireframe, stick or ball and stick molecular skeletons for Amira.
• basin_prob: computes the probabilities of having ν electrons in given basins or group of basins.