[ARCHIVE/2009] Hartree-Fock-Roothan (C++)

• NAIVE implementation of Hartree-Fock method in GTO base,
• ARCHIVAL code written in 2009,
• port of older fortran code to C++,
• GPLv3 LICENSE - use for any purpose as long as you keep copyright note and open source.

Features:

• NAIVE SCF loop - O(N^4) complexity,
• calculates ENERGY and ORBITALS (represented by coefficients in the matrix),
• read molecule GEOMETRY from file,
• GTO BASIS with parameters read from file.

Limitations:

• Only integrals for S orbitals are implemented,
• the number of total electrons in the system MUST BE EVEN (see restricted Hartree-Fock).

Build:

cd src
make

Usage:

• Create input file containing:
  • molecule geometry in cartessian system,
  • basis name to use (basis must be declared within basis.lib file),
  • example h2.inp file is presented below:

GEOM
H 0.0 0.0 0.0
H 0.0 0.0 0.742724
END_GEOM

BASIS 6-31G
HFR

• Run HFR code:

$./hfr h2.inp
Hartree-Fock-Roothan, GNU GPLv3
Copyright (C) 2009, Sylwester Wysocki <sw143@wp.pl>
Source code available at https://github.com/dzik143/hfr-cpp

Loading basis list.................O.K!
Loading element symbols............O.K!
Using job file 'h2.inp'
Loading geometry...................O.K!

INPUT GEOMETRY [au]
-------------------------------
Atom      X      Y      Z
 H   0.00000 0.00000 0.00000
 H   0.00000 0.00000 1.40348
-------------------------------

Using basis set 6-31G...
Loading basis set..................O.K!
Generating atomic orbitals.........O.K!

----------------------------------------------------
 Number of contracted GTO functions: 4
 Number of primitive GTO functions:  8
 Number of one-electron integrals:   64
 Number of two-electron integrals:   1024
 Memory needed to store integrals:   0.004 MB
----------------------------------------------------

Calculating molecular integrals....O.K!
Falling into SCF loop...

iter=1   Etotal=-1.07423828000
iter=2   Etotal=-1.12542019000 delta=5.11819070e-002
iter=3   Etotal=-1.12668272000 delta=1.26253187e-003
iter=4   Etotal=-1.12671112000 delta=2.84026845e-005
iter=5   Etotal=-1.12671175000 delta=6.30249303e-007
iter=6   Etotal=-1.12671177000 delta=1.39565290e-008

SCF convergented.

Molecular orbitals:
 1.120   0.123   0.768   0.327
-1.347   1.708  -0.686   0.272
-1.120  -0.123   0.768   0.327
 1.347  -1.708  -0.686   0.272

Orbital energies:
 1.401
 0.238
 0.776
-0.595