.. tip:: All input files can be downloaded: :download:`Files `. wfn ====== .. contents:: :local: This keyword controls the details of wave function analysis. Options ------------ .. option:: file .. list-table:: :stub-columns: 1 :widths: 5 20 * - Value - File name * - Default - None The file name of the wave function to be analyzed (in MWFN format). .. option:: loc_max_it .. list-table:: :stub-columns: 1 :widths: 5 20 * - Value - An integer * - Default - ``500`` The maximum number of steps for orbital localization. .. option:: loc_cov .. list-table:: :stub-columns: 1 :widths: 5 20 * - Value - A real number * - Default - ``1.E-6`` The convergence threshold for orbital localization. .. option:: print_MO_details When this keyword is presented, much more information will be output for orbital component analysis. Theoretical Background -------------------------------- In Qbics, quantum chemical calculations will produce a wavefunction and store it in a MWFN file. This is a format that contains all the information about the wavefunction, including the molecular coordinates and orbitals. Qbics can read this file and perform some simple wavefunction analysis: - **Orbital localization**: The wavefunction can be localized on atoms. Qbics uses Boys algorithm. - **Orbital component analysis**: The wavefunction can be analyzed in terms of the atomic orbitals. For more kinds of wavefunction analysis, one can use `Qbics-MolStar `_, which uses `Multiwfn `_ as the backend. Please refer to ``_ for more details and correct citation. Input Examples -------------------- Example: Wavefunction Analysis for CH\ :sub:`2`\ O ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Now we perform a wavefunction analysis for CH\ :sub:`2`\ O. The input file is as follows: .. code-block:: bash :linenos: :caption: wfn-1.inp 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 # Do an energy calculation and generate 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: .. code-block:: bash :linenos: :caption: wfn-1.out Molecular orbitals: # Occ O1 C2 H3 H4 total S P D F total S P D F total S P D F total S P D F 1 2.000 0.9997 0.9989 0.0008 0.0000 0.0000 0.0003 0.0001 0.0001 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 2 2.000 0.0009 0.0004 0.0005 0.0000 0.0000 0.9987 0.9986 0.0001 0.0000 0.0000 0.0002 0.0002 0.0000 0.0000 0.0000 0.0002 0.0002 0.0000 0.0000 0.0000 3 2.000 0.9743 0.7996 0.1746 0.0001 0.0000 0.0254 0.0195 0.0058 0.0001 0.0000 0.0001 0.0001 0.0000 0.0000 0.0000 0.0001 0.0001 0.0000 0.0000 0.0000 4 2.000 0.0168 0.0028 0.0138 0.0002 0.0000 0.5906 0.2875 0.3020 0.0011 0.0000 0.3588 0.3571 0.0017 0.0000 0.0000 0.0338 0.0337 0.0001 0.0000 0.0000 5 2.000 0.0168 0.0028 0.0138 0.0002 0.0000 0.5906 0.2875 0.3020 0.0011 0.0000 0.0338 0.0337 0.0001 0.0000 0.0000 0.3588 0.3571 0.0017 0.0000 0.0000 6 2.000 0.5884 0.1161 0.4708 0.0014 0.0000 0.4027 0.1686 0.2318 0.0020 0.0003 0.0044 0.0044 0.0001 0.0000 0.0000 0.0044 0.0044 0.0001 0.0000 0.0000 7 2.000 0.6737 0.0000 0.6716 0.0021 0.0001 0.3259 0.0000 0.3233 0.0024 0.0002 0.0002 0.0000 0.0002 0.0000 0.0000 0.0002 0.0000 0.0002 0.0000 0.0000 8 2.000 0.8530 0.0000 0.8519 0.0010 0.0001 0.0327 0.0000 0.0282 0.0044 0.0001 0.0572 0.0571 0.0000 0.0000 0.0000 0.0572 0.0571 0.0000 0.0000 0.0000 9 0.000 0.4390 0.0000 0.3370 0.0959 0.0061 0.5510 0.0000 0.3801 0.1369 0.0340 0.0050 0.0000 0.0050 0.0000 0.0000 0.0050 0.0000 0.0050 0.0000 0.0000 10 0.000 0.0122 0.0007 0.0114 0.0001 0.0000 0.4747 0.3168 0.1506 0.0060 0.0013 0.5084 0.4970 0.0113 0.0000 0.0000 0.0047 0.0046 0.0001 0.0000 0.0000 11 0.000 0.4033 0.3157 0.0827 0.0049 0.0001 0.5946 0.3464 0.2090 0.0375 0.0018 0.0010 0.0010 0.0000 0.0000 0.0000 0.0010 0.0010 0.0000 0.0000 0.0000 12 0.000 0.0122 0.0007 0.0114 0.0001 0.0000 0.4747 0.3168 0.1506 0.0060 0.0013 0.0047 0.0046 0.0001 0.0000 0.0000 0.5084 0.4970 0.0113 0.0000 0.0000 13 0.000 0.0222 0.0053 0.0167 0.0001 0.0000 0.7300 0.5137 0.2093 0.0054 0.0016 0.2469 0.2432 0.0037 0.0000 0.0000 0.0010 0.0009 0.0001 0.0000 0.0000 14 0.000 0.3324 0.0000 0.1867 0.1329 0.0128 0.6647 0.0000 0.1752 0.3333 0.1562 0.0015 0.0000 0.0015 0.0000 0.0000 0.0015 0.0000 0.0015 0.0000 0.0000 15 0.000 0.0222 0.0053 0.0167 0.0001 0.0000 0.7300 0.5137 0.2093 0.0054 0.0016 0.0010 0.0009 0.0001 0.0000 0.0000 0.2469 0.2432 0.0037 0.0000 0.0000 ... Quantitative atomic contributions for molecular orbitals: 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%) 9, occ = 0.000, over 2 centers: O1(43.90%), C2(55.10%), ==> S(0.00%) + P(72.70%) + D(23.28%) + F(4.02%) 10, occ = 0.000, over 2 centers: C2(47.47%), H3(50.84%), ==> S(81.91%) + P(17.35%) + D(0.60%) + F(0.14%) 11, occ = 0.000, over 2 centers: O1(40.33%), C2(59.46%), ==> S(66.41%) + P(29.17%) + D(4.24%) + F(0.18%) 12, occ = 0.000, over 2 centers: C2(47.47%), H4(50.84%), ==> S(81.91%) + P(17.35%) + D(0.60%) + F(0.14%) 13, occ = 0.000, over 2 centers: C2(73.00%), H3(24.69%), ==> S(76.31%) + P(22.98%) + D(0.55%) + F(0.16%) For example, Line 11 and 30 shows that the molecular orbital ``8`` has an occupation number of ``2.000`` and is localized on the oxygen atom (O1) with a contribution of ``85.30%``. The orbital is mainly composed of the s orbital (``11.42%``) and p orbital (``88.03%``). This is actually an electron lone pair orbital. Using `Qbics-MolStar `_ to open ``wfn-1.mwfn`` and ``wfn-1-loc.mwfn``, we can visualize the canonical and localized orbitals. For example, right-click :guilabel:`wfn-1.mwfn` and select :guilabel:`View Molecular Orbitals`, then select the orbital you want to visualize. Below is an example. Obviously, the canonical orbital is delocalized over the molecule while the localized one is only localized over a bond. .. figure:: figs/wfn-1.jpg