The October issue of=C2=A0Computational Chemistry Highlights=C2=A0is out.

CCH is an=C2=A0 overlay journal=C2=A0that identifies the most= important papers in computational and theoretical chemistry published in t= he last 1-2 years. CCH is not affiliated with any publisher: it is a free r= esource run by scientists for scientists.=C2=A0You can read more about it here.

Table of content fo= r this issue features contributions from CCH editors Steven Bachrach, David= Bowler and Jan Jensen:

Stochastic Multic= onfigurational Self-Consistent Field Theory

Unusual H-Bond Topology and Bifurcated H-bonds in t= he 2-Fluoroethanol Trimer

Benchmarking Continuum Solvent Models for K= eto=E2=80=93Enol Tautomerizations

Mechanism of the Intramolecular H= exadehydro-Diels=E2=80=93Alder Reaction

The accuracy of semi-local f= unctionals

Interested in more?=C2=A0There are many ways to subscribe to CCH updates.=

Also, for your = daily computational chemistry fix subscribe to=C2=A0Computational Chemistry Daily

--001a114570c8846eac05238ae1f4-- From owner-chemistry@ccl.net Mon Nov 2 10:40:01 2015 From: "Thomas Manz thomasamanz**gmail.com" To: CCL Subject: CCL: wiberg bond index Message-Id: <-51842-151102103807-26588-g8cGOv91oePaTKD69x/R7g . server.ccl.net> X-Original-From: Thomas Manz Content-Type: multipart/alternative; boundary=001a113a944006218f05239090f7 Date: Mon, 2 Nov 2015 08:38:02 -0700 MIME-Version: 1.0 Sent to CCL by: Thomas Manz [thomasamanz|,|gmail.com] --001a113a944006218f05239090f7 Content-Type: text/plain; charset=UTF-8 Hi Partha, If you compute the Wiberg bond index in the NAO basis using the NBO program (NBO keyword BNDIDX), it gives a reasonable quantification of bond order in many cases (for hydrogen or other kinds of bonds, whether intermolecular or intramolecular). For spin polarized systems, you have to add twice the sum of the spin-up (alpha) and spin-down (beta) Wiberg bond indices to get the approximate bond order. For spin unpolarized systems, the Wiberg bond indices of the total electron density matrix is used, with no multiplication by two. Effective bond orders quantify the approximate number of electrons exchanged between two atoms. Tom On Sun, Nov 1, 2015 at 10:23 PM, Partha Sengupta anapspsmo%%gmail.com < owner-chemistry{=}ccl.net> wrote: > Friends, I have a question "how Wiberg bond index is related to > intramolecular hydrogen bond ?" > Partha > > -- > > > *Dr. Partha Sarathi SenguptaAssociate ProfessorVivekananda Mahavidyalaya, > Burdwan* > --001a113a944006218f05239090f7 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

Hi Partha,

If you compute the Wiberg bo= nd index in the NAO basis using the NBO program (NBO keyword BNDIDX), it gi= ves a reasonable quantification of bond order in many cases

(for = hydrogen or other kinds of bonds, whether intermolecular or intramolecular)= .

For spin polarized systems, you have to add twic= e the sum of the spin-up (alpha) and spin-down (beta) Wiberg bond indices t= o get the approximate bond order.

For spin unpolarized systems, t= he Wiberg bond indices of the total electron density matrix is used, with n= o multiplication by two.

Effective bond orders qua= ntify the approximate number of electrons exchanged between two atoms.

Tom

On Sun, Nov 1, 2015 at 10:23 PM, Partha Sengupta anapspsmo%%gmail.com <owner-chemistry{=}ccl.net> wrote:

Friends, I have a question "how Wiberg bond index =C2=A0is related to= intramolecular =C2=A0 hydrogen bond ?"
Partha

--
Dr. Partha Sarathi Sengupta
Associate Professo= r
Vivekananda Mahavidyalaya, Burdwan

--001a113a944006218f05239090f7-- From owner-chemistry@ccl.net Mon Nov 2 14:35:01 2015 From: "Tymofii Nikolaienko tim_mail(a)ukr.net" To: CCL Subject: CCL: wiberg bond index Message-Id: <-51843-151102114656-650-AYz63Q0bucDk4EMMu9OW1A*o*server.ccl.net> X-Original-From: Tymofii Nikolaienko Content-Type: multipart/alternative; boundary="------------020303050108080202030101" Date: Mon, 2 Nov 2015 18:46:57 +0200 MIME-Version: 1.0 Sent to CCL by: Tymofii Nikolaienko [tim_mail**ukr.net] This is a multi-part message in MIME format. --------------020303050108080202030101 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit I'd like just to add that a freeware program JANPA ( http://janpa.sourceforge.net/ , see Comput. Theor. Chem. (2014), V.1050, P.15-22 - open access) is also capable of calculating Wiberg bond index in the NAO basis and this program is compatible with a number of freeware quantum chemical packages. Regards, Tymofii On 02.11.2015 17:38, Thomas Manz thomasamanz**gmail.com wrote: > Hi Partha, > > If you compute the Wiberg bond index in the NAO basis using the NBO > program (NBO keyword BNDIDX), it gives a reasonable quantification of > bond order in many cases > (for hydrogen or other kinds of bonds, whether intermolecular or > intramolecular). > > For spin polarized systems, you have to add twice the sum of the > spin-up (alpha) and spin-down (beta) Wiberg bond indices to get the > approximate bond order. > For spin unpolarized systems, the Wiberg bond indices of the total > electron density matrix is used, with no multiplication by two. > > Effective bond orders quantify the approximate number of electrons > exchanged between two atoms. > > Tom > > On Sun, Nov 1, 2015 at 10:23 PM, Partha Sengupta anapspsmo%%gmail.com >

> wrote: > > Friends, I have a question "how Wiberg bond index is related to > intramolecular hydrogen bond ?" > Partha > > -- > */Dr. Partha Sarathi Sengupta > Associate Professor > Vivekananda Mahavidyalaya, Burdwan/* > > --------------020303050108080202030101 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit I'd like just to add that a freeware program JANPA (

http://janpa.sourceforge.net/ , see Comput. Theor. Chem. (2014), V.1050, P.15-22 - open access)
is also capable of calculating Wiberg bond index in the NAO basis and this program is compatible with a number
of freeware quantum chemical packages.

Regards,
Tymofii

On 02.11.2015 17:38, Thomas Manz thomasamanz**gmail.com wrote:

Hi Partha,

If you compute the Wiberg bond index in the NAO basis using the NBO program (NBO keyword BNDIDX), it gives a reasonable quantification of bond order in many cases

(for hydrogen or other kinds of bonds, whether intermolecular or intramolecular).

For spin polarized systems, you have to add twice the sum of the spin-up (alpha) and spin-down (beta) Wiberg bond indices to get the approximate bond order.

For spin unpolarized systems, the Wiberg bond indices of the total electron density matrix is used, with no multiplication by two.

Effective bond orders quantify the approximate number of electrons exchanged between two atoms.

Tom

On Sun, Nov 1, 2015 at 10:23 PM, Partha Sengupta anapspsmo%%gmail.com <owner-chemistry-x-ccl.net> wrote:

Friends, I have a question "how Wiberg bond index is related to intramolecular hydrogen bond ?"

Partha

--

Dr. Partha Sarathi Sengupta
Associate Professor
Vivekananda Mahavidyalaya, Burdwan

--------------020303050108080202030101-- From owner-chemistry@ccl.net Mon Nov 2 18:13:00 2015 From: "Saied Mohammed Soliman saied1soliman .. yahoo.com" To: CCL Subject: CCL: Transition state location for reaction include three reactants Message-Id: <-51844-151102161334-27158-gKt+0WZk73VhCp15rPCSNw^_^server.ccl.net> X-Original-From: "Saied Mohammed Soliman" Date: Mon, 2 Nov 2015 16:13:33 -0500 Sent to CCL by: "Saied Mohammed Soliman" [saied1soliman]-[yahoo.com] Sorry,I was posted an e-mail regarding the transition state location for reaction involve three reactants so may be it was not clear? I have reaction between three reactants A+B+C------Product the suggested mechanism is: 1- A+B-----intermediate then 2- intermediate + C-------final product(regioselective cycloaddition reaction) We expected two products but actually the cycloadditon goes regioselectively to give only one product. I want to explain why? My problem is, how to work on these two steps? or Should I consider only the second step to locate the transition state of the second step only? How can work on the intermediate, is it considered as reactant or considered as a transition state? I mean is the structure of the intermediate should be optimized to an energy minimum or to a transition state Thank you Saied From owner-chemistry@ccl.net Mon Nov 2 20:55:00 2015 From: "teja reddy reddyteja80() gmail.com" To: CCL Subject: CCL: About NBO Analysis Message-Id: <-51845-151102205215-7295-HYdNtXetJS2ps197Pd3RZA||server.ccl.net> X-Original-From: teja reddy Content-Type: multipart/alternative; boundary=001a114714a27dfb6e0523992357 Date: Tue, 3 Nov 2015 07:21:55 +0530 MIME-Version: 1.0 Sent to CCL by: teja reddy [reddyteja80:-:gmail.com] --001a114714a27dfb6e0523992357 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable =E2=80=8Bhello , can anyone explain what is NBO Analysis =E2=80=8Band how r= eliable to assign the nature of bonding. thanks in advance =E2=80=8B =E2=80=8B --=20 *Venkata perareddy B* *Dept. of Chemistry* *NIT,Durgapur=E2=80=8B.India=E2=80=8B* --001a114714a27dfb6e0523992357 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

=E2=80=8Bhello , can anyone explain what is NBO Analysis =E2=80=8Band = how reliable to assign the nature of bonding.

thanks in advance

=E2=80=8B =E2=80=8B

Venkata perareddy B

Dept= . of Chemistry

NIT,Durgapur
=E2=80=8B.India=E2=80=8B

--001a114714a27dfb6e0523992357-- From owner-chemistry@ccl.net Mon Nov 2 22:00:01 2015 From: "Wojciech Kolodziejczyk dziecial..icnanotox.org" To: CCL Subject: CCL: About NBO Analysis Message-Id: <-51846-151102215857-2717-7jq+J5JjBhj9qQY+IcucEw**server.ccl.net> X-Original-From: Wojciech Kolodziejczyk Content-Type: multipart/alternative; boundary=001a11c116021d2d5c05239a12cb Date: Mon, 2 Nov 2015 20:58:39 -0600 MIME-Version: 1.0 Sent to CCL by: Wojciech Kolodziejczyk [dziecial]_[icnanotox.org] --001a11c116021d2d5c05239a12cb Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable I think you can read a lot here http://nbo6.chem.wisc.edu/tutorial.html Or watch this https://www.youtube.com/watch?v=3DC8-8d_dRly8 Wojciech Kolodziejczyk, PhD 2015-11-02 19:51 GMT-06:00 teja reddy reddyteja80() gmail.com < owner-chemistry%a%ccl.net>: > > =E2=80=8Bhello , can anyone explain what is NBO Analysis =E2=80=8Band how= reliable to > assign the nature of bonding. > > > thanks in advance > =E2=80=8B =E2=80=8B > > -- > > *Venkata perareddy B* > > *Dept. of Chemistry* > > *NIT,Durgapur=E2=80=8B.India=E2=80=8B* > --001a11c116021d2d5c05239a12cb Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

I think you can read a lot here

http://nbo6.chem.wisc.edu/tuto= rial.html

Or watch this

https://www.youtube.com/= watch?v=3DC8-8d_dRly8

Wojciech Kolodziejcz= yk, PhD

2015-11-02 19:51 GMT-06:00 teja reddy reddyteja80() gmail.com <owner-chemistry%a%ccl.net>= ;:

=E2=80=8Bhello , can anyon= e explain what is NBO Analysis =E2=80=8Band how reliable to assign the natu= re of bonding.

thanks in advance=
=E2=80=8B =E2= =80=8B

--
Venkata perareddy B
Dept. of Chemistry
NIT,= Durgapur
=E2=80=8B.India=E2=80=8B

--001a11c116021d2d5c05239a12cb--