To install the package, you will call the Julia Package Manager on your REPL:

]add OohataHuzinaga

Done! Now it is ready to use

• Calculates overlap integrals
• Calculate kinetic integrals
• Calculate electron-nuclear attraction integrals
• Calculate electron-electron repulsion integrals

Consider that you want to calculate the electronic energy of a methane molecule. First, you will need the cartesian coordinates of the molecule of interest. This information is stored in our methane.xyz file, formatted as follows:

5

C  0.00001021434087  0.00001532972083 -0.00001493500137
H -0.19951695340554  0.87894179053067 -0.62713882127936
H  0.76712229809243  0.24863902907755  0.74526241504934
H  0.35580334399536 -0.82601803138729 -0.62993342769733
H -0.92343260142312 -0.30159515034176  0.51179839372872

methane = molecule("methane.xyz")

For any molecular calculations, you will need a basis set.

sto3g = buildbasis(methane)

With this information, we can build the molecular integrals.

S = overlap(sto3g, methane)
T = kinetic(sto3g, methane)
V = attraction(sto3g, methane)
G = repulsion(sto3g, methane)