Hi I have a doubt regarding the Mulliken population. I did calculation for NaCl crystal for understanding the analysis of Mulliken population.
I did calculation using DZP basis set and giving Mulliken population as 3.
In the output 2 matrices are given, one for *"overlap population between
orbitals"*, the other is "*overlap population between atoms*" and they give
the *"atomic and orbita*l *populations"* also after these two matrices.
My doubt in it is that the population calculated using the "*overlap
population* *between atoms"* matrix and the population given in *"atomic
and orbital populations*" should be same but they are not.
I am attaching the output here. Please help me in knowing why the
difference in values are there. And also the total of population calculated
using the *"overlap* *population between atoms*" is not equal to the total
number of electrons in the system.
mulliken: Overlap Populations between Atoms
1 2
1 0.254 -0.005
2 -0.005 6.835
Total : * 0.249 6.83 * = * 7.079* ( It should be 8 as in NaCl
unit cell, if we take
valence electrons,
it should be in total 8)
mulliken: Atomic and Orbital Populations:
Species: Na
Atom Qatom Qorb
3s 3s 3Ppy 3Ppz 3Ppx
1 *0.681* 0.061 0.189 0.143 0.143 0.143
Species: Cl
Atom Qatom Qorb
3s 3s 3py 3pz 3px 3py
3pz 3px
3Pdxy 3Pdyz 3Pdz2 3Pdxz 3Pdx2-y2
2 * 7.319 * 1.735 0.106 1.901 1.901 1.901 -0.078
-0.078 -0.078
0.002 0.002 0.001 0.002 0.001
mulliken: Qtot = * 8.000*
Can somebody please help me in knowing why the total population in "
*overlap* *population between atoms*" and in "*atomic and orbital
populations*" are different. All suggestions are welcome. Thanks in
advance.
--
Anju Saroha
Research Scholar
IIT Madras
Chennai-600036
India.
NaCl.out
Description: Binary data
