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Quick Start

This page walks through a complete EDF calculation for H₆ — the simplest test case in the test/ directory.

What you need

  1. A wavefunction file: h6.wfn (GAMESS/Gaussian .wfn format)
  2. An Atomic Overlap Matrix file: h6.aom (from PROMOLDEN or another AOM source)
  3. An input file: h6.edfinp
  4. The edf-omp binary in the parent directory

The input file

0
h6.aom
h6.wfn
ngroup 6
1 1
1 2
1 3
1 4
1 5
1 6
end

Line by line:

Line Content Meaning
0 Record 1 (ioverlap) AOM comes from PROMOLDEN format
h6.aom Record 2 (filedat) Name of the AOM file
h6.wfn Record 3 (wfnfile) Name of the WFN file
ngroup 6 Record 4 Divide the molecule into 6 fragments
1 11 6 Records 5.1–5.6 Each group has 1 basin (atoms 1–6)
end Terminator End of input

Each 1 N line means: "group i contains 1 basin, and that basin is atom N."

Running the calculation

cd test/
OMP_NUM_THREADS=4 ../edf-omp < h6.edfinp > h6_new.edfout
  • OMP_NUM_THREADS=4 uses 4 threads (only effective with edf-omp).
  • Input is read from stdin; output goes to stdout.

What to look for in the output

After the header and wavefunction summary, you will see:

Spin-split probability table

# Spin-Splitted probabilities
# G1(a) G1(b) G2(a) G2(b) ...
#   0.0000000075662346   3  3  0  0  0  0  0  0  0  0  0  0
...

Each row: probability followed by alpha and beta electron counts for each group. G1(a) is the number of alpha electrons in group 1, G1(b) is beta electrons in group 1.

Spinless EDF table

After the spin-resolved table, EDF sums over spin to give total electron counts:

#   0.0002607553   1  1  1  1  1  1    <- dominant: 1 electron per H
#   0.0001234281   2  1  1  1  1  0    <- one H has 2e, one has 0e
...
#   0.999492  <-- SUM,   56 PROBABILITIES

For H₆, the dominant configuration 1 1 1 1 1 1 (one electron per hydrogen) confirms the delocalized ring character.

Average populations and delocalization indices

<n(1)_alpha>  =  0.499746    <- H1 carries 0.5 alpha electrons
<n(1)_beta>   =  0.499746
...
delta_(2 1)   =  0.44337     <- strong delocalization between adjacent H atoms
delta_(3 1)   =  0.06013     <- weaker across the ring

The delocalization index \(\delta(i,j) = 2[\langle n_i n_j \rangle - \langle n_i \rangle \langle n_j \rangle]\) measures electron sharing between fragments.

Next steps

  • Input Format — full description of all input records
  • Output Guide — detailed explanation of each output section
  • Performance — how to get the most out of edf-omp threads