Tip

All input files can be downloaded: Files.

wfn

This keyword controls the details of wave function analysis.

Options

file

Value

File name

Default

None

The file name of the wave function to be analyzed (in MWFN format).

loc_max_it

Value

An integer

Default

500

The maximum number of steps for orbital localization.

loc_cov

Value

A real number

Default

1.E-6

The convergence threshold for orbital localization.

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 http://sobereva.com/multiwfn/ for more details and correct citation.

Input Examples

Example: Wavefunction Analysis for CH2O

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

wfn-1.inp
 1basis
 2    def2-tzvp
 3end
 4
 5wfn
 6    file wfn-1.mwfn  # The file name.
 7    print_MO_details # Print more information.
 8end
 9
10mol
11    O     -0.00000001     -0.00000000      1.44310862
12    C     -0.00000001     -0.00000000      0.24425258
13    H      0.00000004      0.93861213     -0.34368060
14    H     -0.00000002     -0.93861212     -0.34368059
15end
16
17task
18    energy b3lyp # Do an energy calculation and generate wavefunction file: wfn-1.mwfn
19    wfn          # Do analysis.
20end

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:

wfn-1.out
 1Molecular orbitals:
 2   #   Occ  O1                                 C2                                 H3                                 H4
 3            total      S      P      D      F  total      S      P      D      F  total      S      P      D      F  total      S      P      D      F
 4   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
 5   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
 6   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
 7   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
 8   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
 9   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
10   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
11   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
12   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
13  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
14  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
15  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
16  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
17  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
18  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
19...
20Quantitative atomic contributions for molecular orbitals:
21
22Molecular orbitals:
23   1, occ = 2.000, over 1 centers: O1(99.97%), ==> S(99.91%) + P(0.09%) + D(0.00%) + F(0.00%)
24   2, occ = 2.000, over 1 centers: C2(99.87%), ==> S(99.93%) + P(0.07%) + D(0.00%) + F(0.00%)
25   3, occ = 2.000, over 1 centers: O1(97.43%), ==> S(81.93%) + P(18.04%) + D(0.02%) + F(0.00%)
26   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%)
27   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%)
28   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%)
29   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%)
30   8, occ = 2.000, over 1 centers: O1(85.30%), ==> S(11.42%) + P(88.03%) + D(0.53%) + F(0.02%)
31   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%)
32  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%)
33  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%)
34  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%)
35  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 wfn-1.mwfn and select 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.

../_images/wfn-1.jpg