An implementation from scratch of the electronic structure model of [1]; see [2] for details.

• GNU/Linux or Cygwin
• gcc >= 4.7
• make

make qm
make test

./qm qm_m.in <molecule>.{in,out}

• task:%s – calculate energy (energy) or gradient (grad)
• conv:%lf – scf convergence criterion (rms change in density matrix)
• it:%d,%d – number of iterations / size of diis subspace
• print:%d – printing options (1 – default, 2 – print scf vectors, 3 – print atomic charges and bond orders)
• read:%s – file name for reading scf vectors
• write:%s – file name for saving scf vectors
• diis:%d – scf algorithm (0 – straightforward procedure, 1 – diis (default))
• restrict:%d – if the system has an even number of electrons, use 0 – spin-unrestricted or 1 – spin-restricted orbitals
• field:%lf,%lf,%lf – applied electric field (with the opposite sign), i.e. $-\vec E\equiv\nabla\phi$

qm_m.in – the file with the set of parameters (slightly modified qm.in [1a]).

mol/*.in – input files with molecular geometries, the format is described in README [1a]. My program reads the section $molecule only.

mol/*.x.out – corresponding output files from my program.

mol/*.p11.out – corresponding output files from Priroda-11 (we used bin/p1 [1a]).

mol/*.p17.out – corresponding output files from Priroda-17.

[1] D. N. Laikov, J. Chem. Phys. 135, 134120 (2011).

[1a] Supplementary material of [1].

[2] K. R. Briling, J. Chem. Phys. 147, 157101 (2017).