Basis sets

Basis sets#

Basis set specification#

Python script

The choice of basis set is specified with the read method of the MolecularBasis class:

basis = vlx.MolecularBasis.read(molecule, "cc-pVDZ")

Text file

The choice of basis set is specified under method settings:

@method settings
basis: def2-svp
@end

Available basis sets#

The basis sets provided in the VeloxChem library for a specific element can be listed with the get_avail_basis method of the MolecularBasis class.

avail_basis_carbon = vlx.MolecularBasis.get_avail_basis('C')

print('Available basis sets for carbon:\n')

for i in range(0, len(avail_basis_carbon), 6):
    print(', '.join(avail_basis_carbon[i:i + 6]))

Effective-core potential basis sets#

Effective-core potatials are in the process of being implmented in VeloxChem.

Adding a basis set#

You can provide you own basis set file in the job submission directory. The format of this file exeplified below for a single element (carbon), listing separated contracted atomic orbitals (AOs) after one another with specification made of the orbital angular momentum and number of Gaussian primitive functions.

@BASIS_SET my_basis

@ATOMBASIS C
S 6  1
3.047524900000e+03  1.834700000000e-03
4.573695100000e+02  1.403730000000e-02
1.039486900000e+02  6.884260000000e-02
2.921015500000e+01  2.321844000000e-01
9.286663000000e+00  4.679413000000e-01
3.163927000000e+00  3.623120000000e-01
S 3  1
7.868272400000e+00 -1.193324000000e-01
1.881288500000e+00 -1.608542000000e-01
5.442493000000e-01  1.143456400000e+00
P 3  1
7.868272400000e+00  6.899910000000e-02
1.881288500000e+00  3.164240000000e-01
5.442493000000e-01  7.443083000000e-01
S 1  1
1.687144000000e-01  1.000000000000e+00
P 1  1
1.687144000000e-01  1.000000000000e+00
@END
Contents