From owner-chemistry@ccl.net Fri Jun 26 06:30:00 2020 From: "Tian Lu sobereva(~)sina.com" To: CCL Subject: CCL: NBO Question Message-Id: <-54113-200626062701-13811-0v9w3FncpZbswS+Htd4IlA++server.ccl.net> X-Original-From: "Tian Lu" Date: Fri, 26 Jun 2020 06:26:58 -0400 Sent to CCL by: "Tian Lu" [sobereva:sina.com] Hello, Regarding your question, I have a few opinions: 1 Do not focus on "Atom-atom overlap-weighted NAO bond order" and "MO bond order". In my viewpoint they do not have clear physical meaning, and in practice they are not as useful as the "Wiberg bond index matrix in the NAO basis" printed by NBO. 2 If the Wiberg bond index corresponding to this bond is not quite small, and you want to gain a deeper insight into it, you are suggested to use Multiwfn program to decompose the bond index as contributions from interactions between various natural atomic orbitals (NAOs), via this analysis you will make clear which kind of AO combination has relatively significant contribution. See Section 4.9.4 of Multiwfn manual for example of utilizing this analysis. 3 Usually, MO only has very loose relation with bonding, hence it is not useful to examine the bonding nature in terms of MOs. However, if you indeed prefer to examine contribution from MOs, you can use Multiwfn to perform the so-called "orbital occupancy-perturbed Mayer bond order" analysis, which is able to unveil contribution to Mayer bond order (which is similar with Wiberg bond index) from various MOs. Please check Section 4.9.1 of Multiwfn manual for example of performing this kind of analysis. 4 It is worth to note that localized molecular orbital (LMO) has very close relationship with chemical bonding, if you want to examine this bond from an orbital perspective, LMO analysis should be useful. LMO analysis is supported by Multiwfn, and "orbital occupancy-perturbed Mayer bond order" analysis can be performed based on LMO to easily reveal the LMO mostly contributed to a bond. Section 4.19.3 of Multiwfn manual presented a practical example. 5 Recently bond order density (BOD) was proposed in J. Phys. Chem. A, 124, 339 (2020) and has been supported by the latest version of Multiwfn. This method is able to graphically exhibit the electrons having contribution to delocalization index (which is essentially similar with Wiberg bond index), and natural adaptive orbitals (NAdOs) can be generated at the same time to provide a set of orbitals maximally contribute to the bond. This analysis may also be useful for you, see Section 4.200.20 of Multiwfn manual for example. -------------------------------- Best regards, Dr. Tian Lu Beijing Kein Research Center for Natural Sciences, Beijing, P. R. China ----- Original Message ----- > From: "Mark Zottola mzottola!A!gmail.com" Subject: CCL: NBO Question Date: 2020-06-26 11:33 In an NBO analysis I find I have a metal-oxygen bond which has a substantial "atom-atom overlap weighted NAO bond order" (~0.25). These metal oxygen bonds also have a substantial MO bond order (~ 0.33). However, there are no MO's describing the metal-oxygen bonds. Either there is a bond and a combination of AO's to describe that interaction or there is no combination of AO's and there is no bond. Can someone please help me understand this contradiction? Thanks. From owner-chemistry@ccl.net Fri Jun 26 11:34:00 2020 From: "Thomas Manz thomasamanz*|*gmail.com" To: CCL Subject: CCL: NBO Question Message-Id: <-54114-200626113307-8406-jShlJeYtnjKXGtLCg6zBpQ^server.ccl.net> X-Original-From: Thomas Manz Content-Type: multipart/alternative; boundary="000000000000670b4d05a8fe6c9a" Date: Fri, 26 Jun 2020 09:32:47 -0600 MIME-Version: 1.0 Sent to CCL by: Thomas Manz [thomasamanz\a/gmail.com] --000000000000670b4d05a8fe6c9a Content-Type: text/plain; charset="UTF-8" Hi, I would like to add another suggestion regarding Tuan Lu's reply about multiWFN. I suggest the following: (1) Perform Pipek-Mezey localization of the occupied orbitals in multiWFN (item # 4 of Tuan Lu's reply) to see the localized orbitals involved in bonding. (For this to work as expected, each orbital should be fully occupied or fully empty, such as from a Density Functional Theory (DFT) or Hartree-Fock calculation.) You can also view these in multiWFN and export their images. (2) Export a wfx file from multiWFN. This can be done either for the original molecular orbitals and/or for the Pipek-Mezey localized orbitals. Then run the wfx file in the Chargemol program (download from ddec.sourceforge.net) to get the DDEC6 bond orders. These bond orders are the most accurate and versatile ones available today. These bond orders will be identical whether the wfx file included the molecular orbitals or the Pipek-Mezey localized orbitals. Sincerely, Tom On Fri, Jun 26, 2020 at 5:45 AM Tian Lu sobereva(~)sina.com < owner-chemistry#,#ccl.net> wrote: > > Sent to CCL by: "Tian Lu" [sobereva:sina.com] > Hello, > > > Regarding your question, I have a few opinions: > > > 1 Do not focus on "Atom-atom overlap-weighted NAO bond order" and "MO bond > order". In my viewpoint they do not have clear physical meaning, and in > practice they are not as useful as the "Wiberg bond index matrix in the NAO > basis" printed by NBO. > > > 2 If the Wiberg bond index corresponding to this bond is not quite small, > and you want to gain a deeper insight into it, you are suggested to use > Multiwfn program to decompose the bond index as contributions from > interactions between various natural atomic orbitals (NAOs), via this > analysis you will make clear which kind of AO combination has relatively > significant contribution. See Section 4.9.4 of Multiwfn manual for example > of utilizing this analysis. > > > 3 Usually, MO only has very loose relation with bonding, hence it is not > useful to examine the bonding nature in terms of MOs. However, if you > indeed prefer to examine contribution from MOs, you can use Multiwfn to > perform the so-called "orbital occupancy-perturbed Mayer bond order" > analysis, which is able to unveil contribution to Mayer bond order (which > is similar with Wiberg bond index) from various MOs. Please check Section > 4.9.1 of Multiwfn manual for example of performing this kind of analysis. > > > 4 It is worth to note that localized molecular orbital (LMO) has very > close relationship with chemical bonding, if you want to examine this bond > from an orbital perspective, LMO analysis should be useful. LMO analysis is > supported by Multiwfn, and "orbital occupancy-perturbed Mayer bond order" > analysis can be performed based on LMO to easily reveal the LMO mostly > contributed to a bond. Section 4.19.3 of Multiwfn manual presented a > practical example. > > > 5 Recently bond order density (BOD) was proposed in J. Phys. Chem. A, 124, > 339 (2020) and has been supported by the latest version of Multiwfn. This > method is able to graphically exhibit the electrons having contribution to > delocalization index (which is essentially similar with Wiberg bond index), > and natural adaptive orbitals (NAdOs) can be generated at the same time to > provide a set of orbitals maximally contribute to the bond. This analysis > may also be useful for you, see Section 4.200.20 of Multiwfn manual for > example. > > > -------------------------------- > > Best regards, > > > Dr. Tian Lu > Beijing Kein Research Center for Natural Sciences, Beijing, P. R. China > > > ----- Original Message ----- > > From: "Mark Zottola mzottola!A!gmail.com" > Subject: CCL: NBO Question > Date: 2020-06-26 11:33 > > In an NBO analysis I find I have a metal-oxygen bond which has a > substantial "atom-atom overlap weighted NAO bond order" (~0.25). These > metal oxygen bonds also have a substantial MO bond order (~ 0.33). > However, there are no MO's describing the metal-oxygen bonds. > > Either there is a bond and a combination of AO's to describe that > interaction or there is no combination of AO's and there is no bond. Can > someone please help me understand this contradiction? > > Thanks.> > > --000000000000670b4d05a8fe6c9a Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Hi,

I would like to add another suggest= ion regarding Tuan Lu's reply about multiWFN. I suggest the following:<= /div>

(1) Perform Pipek-Mezey localization of the occupi= ed orbitals in multiWFN (item # 4 of Tuan Lu's reply) to see the locali= zed orbitals involved in bonding. (For this to work as expected, each orbit= al should be fully occupied or fully empty, such as from a Density Function= al Theory (DFT) or Hartree-Fock calculation.) You can also view these in mu= ltiWFN and export their images.

(2) Export a wfx f= ile from multiWFN. This can be done either for the original molecular orbit= als and/or for the Pipek-Mezey localized orbitals. Then run the wfx file in= the Chargemol program (download from ddec.sourceforge.net) to get the DDEC6 bond orders. These bond order= s are the most accurate and versatile ones available today. These bond orde= rs will be identical whether the wfx file included the molecular orbitals o= r the Pipek-Mezey=20 localized orbitals.

Sincerely,

Tom

On Fri, Jun 26, 2020 at 5:45 AM Tian Lu sobereva(~)sina.com <owner-chemistry#,#ccl.net> wrote:

Sent to CCL by: "Tian=C2=A0 Lu" [sobereva:sina.com]
Hello,


Regarding your question, I have a few opinions:


1 Do not focus on "Atom-atom overlap-weighted NAO bond order" and= "MO bond order". In my viewpoint they do not have clear physical= meaning, and in practice they are not as useful as the "Wiberg bond i= ndex matrix in the NAO basis" printed by NBO.


2 If the Wiberg bond index corresponding to this bond is not quite small, a= nd you want to gain a deeper insight into it, you are suggested to use Mult= iwfn program to decompose the bond index as contributions from interactions= between various natural atomic orbitals (NAOs), via this analysis you will= make clear which kind of AO combination has relatively significant contrib= ution. See Section 4.9.4 of Multiwfn manual for example of utilizing this a= nalysis.


3 Usually, MO only has very loose relation with bonding, hence it is not us= eful to examine the bonding nature in terms of MOs. However, if you indeed = prefer to examine contribution from MOs, you can use Multiwfn to perform th= e so-called "orbital occupancy-perturbed Mayer bond order" analys= is, which is able to unveil contribution to Mayer bond order (which is simi= lar with Wiberg bond index) from various MOs. Please check Section 4.9.1 of= Multiwfn manual for example of performing this kind of analysis.


4 It is worth to note that localized molecular orbital (LMO) has very close= relationship with chemical bonding, if you want to examine this bond from = an orbital perspective, LMO analysis should be useful. LMO analysis is supp= orted by Multiwfn, and "orbital occupancy-perturbed Mayer bond order&q= uot; analysis can be performed based on LMO to easily reveal the LMO mostly= contributed to a bond. Section 4.19.3 of Multiwfn manual presented a pract= ical example.


5 Recently bond order density (BOD) was proposed in J. Phys. Chem. A, 124, = 339 (2020) and has been supported by the latest version of Multiwfn. This m= ethod is able to graphically exhibit the electrons having contribution to d= elocalization index (which is essentially similar with Wiberg bond index), = and natural adaptive orbitals (NAdOs) can be generated at the same time to = provide a set of orbitals maximally contribute to the bond. This analysis m= ay also be useful for you, see Section 4.200.20 of Multiwfn manual for exam= ple.


--------------------------------

Best regards,


Dr. Tian Lu
Beijing Kein Research Center for Natural Sciences, Beijing, P. R. China


----- Original Message -----
> From: "Mark Zottola mzottola!A!gmail.com" <owner-chemistry]|= [ccl.net>
Subject: CCL: NBO Question
Date: 2020-06-26 11:33

In an NBO analysis I find I have a metal-oxygen bond which has a substantia= l "atom-atom overlap weighted NAO bond order" (~0.25).=C2=A0 Thes= e metal oxygen bonds also have a substantial MO bond order (~ 0.33).=C2=A0 = However, there are no MO's describing the metal-oxygen bonds.

Either there is a bond and a combination of AO's to describe that inter= action or there is no combination of AO's and there is no bond.=C2=A0 C= an someone please help me understand this contradiction?

Thanks.



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