Multiwfn forum

TZ588

Member

Registered: 2018-07-21

Posts: 2

(3,-3) critical points are missing

I am studying a system, Li6, optimized in Firefly/GAMESS.  I create the wfn file from the PUNCH archive and submit it to Multiwfn.  THere is no problem as it reads the file.  The analysis for (3,-3), (3,-1) and (3,+1) data points seems to work.  But when I visualize the output, I get 9 (3,-3) CP instead of 6 for the Li atoms (no other atoms in the system).  I get 3 (3,-1) bond CP and 1 (3,+1) ring CP.  I know this violates the Poincare-Hopf relationship.

I examined Li2 using the same basis set (6-311g+*) as I did Li6.  The topological analysis proceeded normally - 2 (3,-3) CP, 1 (3,-1) bond cp and a bond path through the bcp connecting the two (3,-3) critical points.  I am confused.  I do not know if I have done something wrong or if I have hit upon a bug.

I have attached my wfn file for your perusal.  Any help is indeed welcome!

li7.wfn

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,468

Website

Re: (3,-3) critical points are missing

This system is somewhat special, since there are three pseudoatoms, which also known as NNA (non-nuclear attractor), these kind of (3,-3) CPs do not occur at nuclear positions. The reason of occurence of these NNAs is that Li atoms tend to contribute their valence electron to form metallic bond in their overlap regions. In order to locate all CPs in such a system, you should use below steps after loading the .wfn file:

2  // Topology analysis module
2  // Search CPs from nuclear positions
3  // Search CPs from midpoint of atom pairs
6  // Search CPs from a batch of points within a sphere
-1 // Start the search using each nucleus as sphere center in turn
-9 // Return to topology analysis interface
Now use option 0, you will see below graph

As can be seen, PH relationship has been satisfied, all (3,-3) CPs and all related BCPs and RCPs have been found.