wfn

This keyword controls the details of wave function analysis.

Options

Theoretical Background

In Qbics, quantum chemical calculations will produce a wavefunction and store it in an MWFN file. This format contains all the information about the wavefunction, including molecular coordinates and orbitals. Qbics can read this file and perform some basic wavefunction analyses:

• Orbital localization: The wavefunction can be localized on atoms. Qbics uses the Boys algorithm.
• Orbital component analysis: The wavefunction can be analyzed in terms of atomic orbitals.

For more advanced wavefunction analyses, one can use Multiwfn. Qbics is fully compatible with Multiwfn.

Input Examples

Example: Wavefunction Analysis for CH₂O

Now we perform a wavefunction analysis for CH₂O. The input file is as follows:

basis
    def2-tzvp
end

wfn
    file wfn-1.mwfn  # The file name.
    print_MO_details # Print more information.
end

mol
    O     -0.00000001     -0.00000000      1.44310862
    C     -0.00000001     -0.00000000      0.24425258
    H      0.00000004      0.93861213     -0.34368060
    H     -0.00000002     -0.93861212     -0.34368059
end

task
    energy b3lyp # Perform an energy calculation and generate the wavefunction file: wfn-1.mwfn.
    wfn          # Do analysis.
end

After calculation, there will be 2 MWFN files:

• wfn-1.mwfn: Stores the original canonical molecular orbitals.
• wfn-1-loc.mwfn: Stores the localized molecular orbitals.

The output file also contains atomic orbital components:

Molecular orbitals:
   1, occ = 2.000, over 1 centers: O1(99.97%), ==> S(99.91%) + P(0.09%) + D(0.00%) + F(0.00%)
   2, occ = 2.000, over 1 centers: C2(99.87%), ==> S(99.93%) + P(0.07%) + D(0.00%) + F(0.00%)
   3, occ = 2.000, over 1 centers: O1(97.43%), ==> S(81.93%) + P(18.04%) + D(0.02%) + F(0.00%)
   4, occ = 2.000, over 2 centers: C2(59.06%), H3(35.88%), ==> S(68.11%) + P(31.75%) + D(0.13%) + F(0.00%)
   5, occ = 2.000, over 2 centers: C2(59.06%), H4(35.88%), ==> S(68.11%) + P(31.75%) + D(0.13%) + F(0.00%)
   6, occ = 2.000, over 2 centers: O1(58.84%), C2(40.27%), ==> S(29.35%) + P(70.27%) + D(0.34%) + F(0.04%)
   7, occ = 2.000, over 2 centers: O1(67.37%), C2(32.59%), ==> S(0.00%) + P(99.53%) + D(0.45%) + F(0.03%)
   8, occ = 2.000, over 1 centers: O1(85.30%), ==> S(11.42%) + P(88.03%) + D(0.53%) + F(0.02%)