QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: jjhskang on November 10, 2011, 00:55

Title: How can I interprete the result of Mulliken population analysis?
Post by: jjhskang on November 10, 2011, 00:55

Hi!

I have difficulty in interprteting Mulliken polulation result. For example, what does each line in the following example correspond to? Why are there 6 lines ? The last two lines seem to correspond to P orbitals. Are they for 5p and 4p?
What is order? "4d, 4s,....."

I would appreciate if somebody can explain this.





Mulliken Population Report                                                   |
|                                                                              |
| ---------------------------------------------------------------------------- |
|                        |                                                     |
| Element   Total  Shell | Orbitals                                            |
|                        |                                                     |
|                        |     xy     zy  zz-rr     zx  xx-yy                  |
|      0  Ag   11.005  1.267 |  0.253  0.253  0.255  0.253  0.253                 |
|                        |      s                                              |
|                 -0.014 | -0.014                                              |
|                        |     xy     zy  zz-rr     zx  xx-yy                  |
|                  8.202 |  1.638  1.650  1.627  1.650  1.638                  |
|                        |      s                                              |
|                  0.801 |  0.801                                              |
|                        |      y      z      x                                |
|                  0.011 |  0.004  0.002  0.004                                |
|                        |      y      z      x                                |
|                  0.740 |  0.246  0.247  0.247   

Title: Re: How can I interprete the result of Mulliken population analysis?
Post by: zh on November 10, 2011, 01:43

Your results may be obtained using the DZDP basis set, so the data of Mulliken population contain 6 lines.  They correspond to 4d (the 1st and 3rd lines), 5s (the 2nd and 4th lines), and 5p (the 5th and 6th lines). The last two lines correspond to the projection onto the polarized orbitals of 5p. 

Title: Re: How can I interprete the result of Mulliken population analysis?
Post by: jjhskang on November 10, 2011, 05:13

Yes, that for DZDP basis set.
So, do they represent 4d 5s 4d 5s .... in sequence ?

Title: Re: How can I interprete the result of Mulliken population analysis?
Post by: kstokbro on November 10, 2011, 09:00

seems something is wrong with the indentation in your output,
The report gives the mulliken population per atom, shell and orbital.
The following should be more clear:


Mulliken Population Report                                                   |
|                                                                              |
| ---------------------------------------------------------------------------- |
|                        |                                                     |
| Element   Total      Shell | Orbitals                                            |
|                                        |                                                         |
|                                        |     xy     zy  zz-rr     zx  xx-yy          |
|      0  Ag   11.005  1.267 |  0.253  0.253  0.255  0.253  0.253  |
|                                        |      s                                                                |
|                             -0.014 | -0.014                                              |
|                                        |     xy     zy  zz-rr     zx  xx-yy                  |
|                              8.202 |  1.638  1.650  1.627  1.650  1.638                  |
|                                        |      s                                              |
|                              0.801 |  0.801                                              |
|                                        |      y      z      x                                |
|                              0.011 |  0.004  0.002  0.004                                |
|                                        |      y      z      x                                |
|                              0.740 |  0.246  0.247  0.247   

Title: Re: How can I interprete the result of Mulliken population analysis?
Post by: Anders Blom on November 10, 2011, 10:17

Tip: for formatted output, enclose the contents in a "code" box.

The ATK basis sets only roughly correspond to the orbitals of the isolated atom. The role of the basis set is to provide functions in which we expand the electron density, and in principle they can be very different from atomic orbitals. In the particular method used in ATK, the are indeed atomic-like, and in your case the basis set consists of 2 sets of orbitals of s-type symmetry, 2 sets of p-type, and one set of d-type. The s and d orbitals with decent occupations can of course be said to correspond quite closely to the 4d and 5s shells, but clearly there is also some p-type components. This doesn't really correspond to occupied 5p orbitals, it's just how the electron cloud looks in the crystal, which of course is quite different from the isolated Ag atom.