Multiwfn forum

qadir

Member

Registered: 2017-12-21

Posts: 2

Multi-configurational WF analysis

Dear Multiwfn Developers,

First---thank you for your wonderful work and for kindly making it available to the community!

Now, to my question: I have a molden file with a set of natural orbitals (NOs) generated from MRCI calculation (with Molpro) which I'd like to use to perform molecular surface analysis (I'm trying to validate the analysis of the ESP features obtained with DFT against high-level multi-reference methods---the molecule I'm working with is pretty tricky). The question is, does Multiwfn use all NOs, including those with small occupation, to generate the electron density/ESP for the analysis?

The analysis works fine and gives reasonable results, but I noticed that when I try to simply generate an electron density grid (option 5) Multiwfn prints a message "Virtual orbitals higher than LUMO+10 have been discarded for saving computational time", which in my case could lead to significant error.**

If the surface analysis also discards most of the orbitals with low occupation (beyond LUMO+10), is there a way to tell it to use all NOs for the calculation without re-compiling the code?

Thanks again for your work!

Best,
-Qadir

**Unfortunately, Multiwfn crashes with a Segmentation fault when I try to use option 5, so I cannot compare the grids generated with option 5 vs option 12).

Last edited by qadir (2017-12-21 21:52:46)

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,758

Website

Re: Multi-configurational WF analysis

Dear qadir,

Please simply ignore the prompt "Virtual orbitals higher than LUMO+10 have been discarded for saving computational time", it never affects result, all NOs are taken into account. In the next version it will not be shown again when wavefunction is represented by NOs. Thank you for reporting this issue.

The most common reason leading to segmentation fault when using main function 5 is that the system limits the use of memory under default setting. If the Multiwfn was installed strictly according the way described in Section 2.1.2 of the manual, segmentation fault should not occur.

Best wishes,

Tian Lu

qadir

Member

Registered: 2017-12-21

Posts: 2

Re: Multi-configurational WF analysis

Dear Tian,

Thanks a lot for a prompt reply, you are right---the segfault was because I forgot to increase the stack size, it works great now!

Cheers,
-Qadir