From owner-chemistry@ccl.net Thu Jun 30 01:14:01 2016 From: "Wojciech Kolodziejczyk dziecial%a%icnanotox.org" To: CCL Subject: CCL: NBO Message-Id: <-52261-160630011008-7712-BZ3ZruyQLjACxJ1vDIoyRw/a\server.ccl.net> X-Original-From: Wojciech Kolodziejczyk Content-Type: multipart/alternative; boundary=94eb2c075c4ad37e95053677e1ca Date: Thu, 30 Jun 2016 00:10:00 -0500 MIME-Version: 1.0 Sent to CCL by: Wojciech Kolodziejczyk [dziecial^-^icnanotox.org] --94eb2c075c4ad37e95053677e1ca Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sir, did you get my last email? W. 2016-06-28 8:10 GMT-05:00 Partha Sengupta anapspsmo##gmail.com < owner-chemistry_._ccl.net>: > I have five structures. Will you help me doing the NBO of those species? > PSSengupta > > On Sun, Jun 26, 2016 at 10:44 PM, Wojciech Kolodziejczyk dziecial],[ > icnanotox.org wrote: > >> What is your problem? >> 26 cze 2016 11:43 "Partha Sengupta anapspsmo]=3D[gmail.com" < >> owner-chemistry_-_ccl.net> napisa=C5=82(a): >> >>> Friends, Is there any one who can help me doing some NBO analysis with >>> NBO 6 package. >>> Partha >>> >>> -- >>> >>> >>> *Dr. Partha Sarathi SenguptaAssociate ProfessorVivekananda >>> Mahavidyalaya, Burdwan* >>> >> > > > -- > > > *Dr. Partha Sarathi SenguptaAssociate ProfessorVivekananda Mahavidyalaya, > Burdwan* > --94eb2c075c4ad37e95053677e1ca Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Sir, did you get my last email?
W.



2016-06= -28 8:10 GMT-05:00 Partha Sengupta anapspsmo##= gmail.com <owner-chemistry_._ccl.net>:
I have five structures. Will you= help me doing the NBO of those species?
PSSengupta

On Sun, Jun 26, 2016 a= t 10:44 PM, Wojciech Kolodziejczyk dziecial],[icnanotox.org <owner-chemistry a ccl.net= > wrote:

Wha= t is your problem?

26 cze 2016 11:43 "Partha Sengupta anapspsm= o]=3D[gmail.com" &l= t;owner-chem= istry_-_ccl.net> napisa=C5=82(a):
Friends, Is there any one who ca= n help me doing some NBO analysis with NBO 6 package.
Partha

--=
Dr. Partha Sarathi Sengupta
Associate Professor
Vivekananda Mahavid= yalaya, Burdwan



--
Dr. Partha Sarathi Sengupta<= br>Associate Professor
Vivekananda Mahavidyalaya, Burdwan=

--94eb2c075c4ad37e95053677e1ca-- From owner-chemistry@ccl.net Thu Jun 30 11:54:01 2016 From: "Tandon Swetanshu tandons#%#tcd.ie" To: CCL Subject: CCL: Coupling constant (Jab) - Why more unpaired electrons means a smaller coupling? Message-Id: <-52262-160630112455-24201-pim2JxRVHdT+yVuwgui01g=server.ccl.net> X-Original-From: Tandon Swetanshu Content-Type: multipart/alternative; boundary=001a113d1636857f710536807885 Date: Thu, 30 Jun 2016 16:24:48 +0100 MIME-Version: 1.0 Sent to CCL by: Tandon Swetanshu [tandons-x-tcd.ie] --001a113d1636857f710536807885 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi Henrique, Thanks again for the advice. I think however, that you were referring to coming up with different models (each generally having a different number of coupling constants) before proceeding with the calculation of coupling constants (please correct me if I am wrong). For the system I am studying, I have selected the model. The number of equations I have for calculating the coupling constants is much greater than the number of coupling constants that I need to calculate. Depending upon the set of equations I choose, I get a different set of J values. Can you please guide me as to how should I choose the appropriate set of equation for calculating the J values. Thanks again, Swetanshu. On 29 June 2016 at 12:01, Henrique C. S. Junior henriquecsj~~gmail.com < owner-chemistry!=!ccl.net> wrote: > Hi, Swetanshu, > You don't need the coupling constants before, but you need to perform a > study to understand what couplings are relevant to your system (to figure > out how complex the Hamiltonian will be). After you understood your syste= m, > you can use, as an example, the software DAVE[1] to see if your model fit= s > your experimental data. If not, you have to re-think your system and try > again to obtain a better fit. > > [1] - https://www.ncnr.nist.gov/dave/download.html > > 2016-06-28 16:53 GMT-03:00 Tandon Swetanshu tandons-,-tcd.ie < > owner-chemistry(a)ccl.net>: > >> Hi Henrique, >> >> Thanks a lot for the insight. I have a small doubt. Before obtaining the >> susceptibility curve, we need to obtain the coupling constant. So can't = we >> just compare the calculated coupling constants with the experimental one= s? >> >> Thanks again, >> Swetanshu. >> >> On 26 June 2016 at 22:05, Henrique C. S. Junior henriquecsj(~)gmail.com = < >> owner-chemistry!!ccl.net> wrote: >> >>> Hi, Swetanshu, >>> It is not an easy task to decide what configuration is correct to >>> describe the magnetic couplings in a polynuclear system. The best appro= ach >>> is to compare the various solutions with an experimental magnetic >>> susceptibility curve using a statistical fit software (like origin). >>> >>> >>> >>> ---------- >>> *Henrique C. S. Junior* >>> Qu=C3=ADmico Industrial - UFRRJ >>> Mestrando em Qu=C3=ADmica Inorg=C3=A2nica - UFRRJ >>> Centro de Processamento de Dados - PMP >>> >>> >>> ------------------------------ >>> > From: owner-chemistry=C3=8Cl.net >>> To: henriquecsjgmail.com >>> Subject: CCL: Coupling constant (Jab) - Why more unpaired electrons >>> means a smaller coupling? >>> Date: Fri, 24 Jun 2016 11:45:36 +0100 >>> >>> Hi All, >>> >>> I have a question somewhat related to this topic. When working out the = J >>> values in a system with more than 3 metal atoms, there are many differe= nt >>> solutions. Each solutions is obtained by choosing a different set of >>> equations. From the above discussion it seems to me that the large >>> differeence in the solutions are due to the large number of unpaired >>> electrons and the reduction in the spacing between levels at higher ene= rgy. >>> Due to this, depending upon the states under consideration the J values >>> obtained would differ (please correct me if I am wrong). But how does o= ne >>> decide as to which set of solution is appropriate. >>> >>> Thanks, >>> Swetanshu. >>> >>> On 12 June 2016 at 00:27, James Buchwald buchwja/rpi.edu < >>> owner-chemistry,ccl.net> wrote: >>> >>> Hi Henrique, >>> >>> The diminishing Jab that you're predicting assumes that (E[HS] - E[BS]) >>> does not grow as quickly as the spin term in the denominator. Dependin= g on >>> the system, this is not necessarily the case, and the energy spacing ca= n >>> grow faster. >>> >>> The reason that the equations appear to cause this is that the >>> Heisenberg-Dirac-van Vleck Hamiltonian (which the three equations were >>> derived from) has a "spin ladder" of solutions ranging from the low-spi= n to >>> the high-spin states. If your low-spin state is a singlet, you'll also >>> have triplets, pentets, and so on until you reach the high-spin state. >>> Similarly, if you start from a doublet, you'll have intermediate quarte= ts, >>> etc. >>> >>> As you introduce more and more unpaired electrons, the spin of the >>> high-spin state increases - but all of the intermediate states between = the >>> high-spin and low-spin limits still exist. You can work out the splitt= ing >>> between these individual states in terms of J, and what ends up happeni= ng >>> is that the states spread out. The denominator essentially corrects fo= r >>> that spacing, rather than saying anything about the strength of the >>> magnetic coupling. >>> >>> Best, >>> James >>> >>> On 06/11/2016 05:54 PM, Henrique C. S. Junior henriquecsj-x-gmail.com >>> wrote: >>> >>> I hope this is not a "homework" question, but I'm having a bad time >>> trying to figure this out. >>> Available literature proposes 3 equations to calculate the coupling >>> constant during a Broken-Symmetry approach: >>> >>> J(1) =3D -(E[HS]-E[BS])/Smax**2 >>> J(2) =3D -(E[HS]-E[BS])/(Smax*(Smax+1)) >>> J(3) =3D -(E[HS]-E[BS])/(HS-BS) >>> >>> I'm intrigued by the fact that, from the equations, the more the system >>> have unpaired electrons, the minor will be Jab. Why does this happen? >>> Doesn't more unpaired electrons increase magnetic momenta (and an incre= ase >>> in magnetic coupling)? >>> >>> -- >>> *Henrique C. S. Junior* >>> Qu=C3=ADmico Industrial - UFRRJ >>> Mestrando em Qu=C3=ADmica Inorg=C3=A2nica - UFRRJ >>> Centro de Processamento de Dados - PMP >>> >>> >>> -- >>> James R. Buchwald >>> Doctoral Candidate, Theoretical Chemistry >>> Dinolfo Laboratory >>> Dept. of Chemistry and Chemical Biology >>> Rensselaer Polytechnic Institutehttp://www.rpi.edu/~buchwj >>> >>> >>> >> > > > -- > *Henrique C. S. Junior* > Qu=C3=ADmico Industrial - UFRRJ > Mestrando em Qu=C3=ADmica Inorg=C3=A2nica - UFRRJ > Centro de Processamento de Dados - PMP > --001a113d1636857f710536807885 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Hi Henrique,

Thanks again for = the advice. I think however, that you were referring to coming up with diff= erent models (each generally having a different number of coupling constant= s) before proceeding with the calculation of coupling constants (please cor= rect me if I am wrong). For the system I am studying, I have selected the m= odel. The number of equations I have for calculating the coupling constants= is much greater than the number of coupling constants that I need to calcu= late. Depending upon the set of equations I choose, I get a different set o= f J values. Can you please guide me as to how should I choose the appropria= te set of equation for calculating the J values.

Thanks again,=
Swetanshu.

On 29 June 2016 at 12:01, Henrique C. S. Junior henriquecsj~~<= a href=3D"http://gmail.com">gmail.com <owner-chemistry!=!ccl.net> wrote:
Hi,=C2= =A0Swetanshu,=
You = don't need the coupling constants before, but you need to perform a stu= dy to understand what couplings are relevant to your system (to figure out = how complex the Hamiltonian will be). After you understood your system, you= can use, as an example, the software DAVE[1] to see if your model fits you= r experimental data. If not, you have to re-think your system and try again= to obtain a better fit.

[1] -=C2=A0https://www.ncnr.nist.gov/dave/download.html

2016-06-28 16:53 GMT-03:00 Tandon Swetanshu tandons-,-tcd.ie <owner-chemistry(a)ccl.net>:
Hi Henrique,

Thanks a lot for the insight. I have a smal= l doubt. Before obtaining the susceptibility curve, we need to obtain the c= oupling constant. So can't we just compare the calculated coupling cons= tants with the experimental ones?

Thanks again,
Swet= anshu.

O= n 26 June 2016 at 22:05, Henrique C. S. Junior henriquecsj(~)gmail.com <owner-chemistry!!cc= l.net> wrote:
Hi, S= wetanshu,
It is not an easy task to d= ecide what configuration is correct to describe the magnetic couplings in a= polynuclear system. The best approach is to compare the various solutions = with an experimental magnetic susceptibility curve using a statistical fit = software (like origin).



-= ---------
Henri= que C. S. Junior
Qu=C3=ADmico Industrial - UFRRJ
Mestrando em Qu=C3=ADmica Inorg=C3= =A2nica - UFRRJ
Centro de Processamento de Dados - PMP


= > From: owner-chemistry=C3=8Cl.net
To: henriquecsjgmail.com
Subject: CCL: Coupl= ing constant (Jab) - Why more unpaired electrons means a smaller coupling?<= br>Date: Fri, 24 Jun 2016 11:45:36 +0100

Hi All,
I have a question somewhat related to this topic. When wor= king out the J values in a system with more than 3 metal atoms, there are m= any different solutions.=C2=A0 Each solutions is obtained by choosing a dif= ferent set of equations. From the above discussion it seems to me that the = large differeence in the solutions are due to the large number of unpaired = electrons and the reduction in the spacing between levels at higher energy.= Due to this, depending upon the states under consideration the J values ob= tained would differ (please correct me if I am wrong). But how does one dec= ide as to which set of solution is appropriate.

Thanks,
Swetanshu.

On 12 June 2016 at 00:27= , James Buchwald buchwja/rpi.e= du <owner-chemistry,ccl.net> wrote:
=20 =20 =20
Hi Henrique,

The diminishing Jab that you're predicting assumes that (E[HS] - E[BS]) does not grow as quickly as the spin term in the denominator.=C2=A0 Depending on the system, this is not necessarily the case, and the energy spacing can grow faster.

The reason that the equations appear to cause this is that the Heisenberg-Dirac-van Vleck Hamiltonian (which the three equations were derived from) has a "spin ladder" of solutions ranging f= rom the low-spin to the high-spin states.=C2=A0 If your low-spin state is a singlet, you'll also have triplets, pentets, and so on until you reach the high-spin state.=C2=A0 Similarly, if you start from a doublet= , you'll have intermediate quartets, etc.

As you introduce more and more unpaired electrons, the spin of the high-spin state increases - but all of the intermediate states between the high-spin and low-spin limits still exist.=C2=A0 You can wo= rk out the splitting between these individual states in terms of J, and what ends up happening is that the states spread out.=C2=A0 The denominator essentially corrects for that spacing, rather than saying anything about the strength of the magnetic coupling.

Best,
James

On 06/11/2016 05:54 PM, Henrique C. S. Junior h= enriquecsj-x-gmail.com wrote:
I hope this is not a "homework" question, but I'm= having a bad time trying to figure this out.
Available literature proposes 3 equations to calculate the coupling constant during a Broken-Symmetry approach:

J(1) =3D -(E[HS]-E[BS])/Smax**2
J(2) =3D -(E[HS]-E[BS])/(Smax*(Smax+1))
J(3) =3D -(E[HS]-E[BS])/(<S**2>HS-<S**2>BS)

I'm intrigued by the fact that, from the equations, the more the system have unpaired electrons, the minor will be Jab. Why does this happen? Doesn't more unpaired electrons increase magnetic momenta (and an increase in magnetic coupling)?

--
<= font face=3D"monospace, monospace">Henrique C. S= . Junior
Qu=C3=ADmico Industrial - UFRRJ
<= font face=3D"monospace, monospace">Mestrando em Qu=C3=ADmica Inorg=C3=A2nica - UFRRJ
Centro de Processamento de Dados - PMP
= 
--=20
James R. Buchwald
Doctoral Candidate, Theoretical Chemistry
Dinolfo Laboratory
Dept. of Chemistry and Chemical Biology
Rensselaer Polytechnic Institute
http://www.rpi.edu=
/~buchwj

<= /span>


--
= = Henrique C. S. Junior
Qu=C3=ADmico= Industrial - UFRRJ
Mestrando em Qu=C3= =ADmica Inorg=C3=A2nica - UFRRJ
Centro de Processamento de Dados - PMP
--001a113d1636857f710536807885-- From owner-chemistry@ccl.net Thu Jun 30 13:17:00 2016 From: "Tobias Kraemer t.kraemer:+:hw.ac.uk" To: CCL Subject: CCL: Coupling constant (Jab) - Why more unpaired electrons means a smaller coupling? Message-Id: <-52263-160630130311-21905-a6IA68cPAHUd6ukX8mE5Xw##server.ccl.net> X-Original-From: "Tobias Kraemer" Date: Thu, 30 Jun 2016 13:03:08 -0400 Sent to CCL by: "Tobias Kraemer" [t.kraemer|hw.ac.uk] Dear Swetanshu, in your case you are dealing with an overdetermined system of linear equations, i.e. there are more equations than needed to solve for all coupling constants (J_ab). You can use the so-called singular value decompostion (SVD) method to solve for the best set of J_ab. Basically you consider all your equations resulting from all combinations of spin configurations (high-spin plus numerous broken-symmetry solutions). MATLAB can do this job for you, you only have to input the matrices with the coefficients and J_ab variables, run SVD and you'll have your result. I can't find any particular literature on this at the moment, but there are plenty of papers on this. This one here by Michl et al. mentions SVD: Toward (car)boranebased molecular magnetsm Theor. Chem. Acc. (2015) 134:9 Hope this helps Tobi Dr. Tobias Kraemer MRSC Research Associate Institute of Chemical Sciences School of Engineering & Physical Sciences Heriot-Watt University Edinburgh EH14 4AS United Kingdom email: t.kraemer:_:hw.ac.uk phone: +44 (0)131 451 3259 >Hi Henrique, >Thanks again for the advice. I think however, that you were referring to >coming up with different models (each generally having a different number >of coupling constants) before proceeding with the calculation of coupling >constants (please correct me if I am wrong). For the system I am studying, >I have selected the model. The number of equations I have for calculating >the coupling constants is much greater than the number of coupling >constants that I need to calculate. Depending upon the set of equations I >choose, I get a different set of J values. Can you please guide me as to >how should I choose the appropriate set of equation for calculating the J >values. >Thanks again, >Swetanshu. > "Henrique C. S. Junior henriquecsj~~gmail.com" wrote: > > Sent to CCL by: "Henrique C. S. Junior" [henriquecsj+*+gmail.com] > --001a113dd29432bd3c053668ae65 > Content-Type: text/plain; charset=UTF-8 > Content-Transfer-Encoding: quoted-printable > > Hi, Swetanshu, > You don't need the coupling constants before, but you need to perform a > study to understand what couplings are relevant to your system (to figure > out how complex the Hamiltonian will be). After you understood your system, > you can use, as an example, the software DAVE[1] to see if your model fits > your experimental data. If not, you have to re-think your system and try > again to obtain a better fit. > > [1] - https://www.ncnr.nist.gov/dave/download.html > > 2016-06-28 16:53 GMT-03:00 Tandon Swetanshu tandons-,-tcd.ie < > owner-chemistry.:.ccl.net>: > > > Hi Henrique, > > > > Thanks a lot for the insight. I have a small doubt. Before obtaining the > > susceptibility curve, we need to obtain the coupling constant. So can't w= > e > > just compare the calculated coupling constants with the experimental ones= > ? > > > > Thanks again, > > Swetanshu. > > > > On 26 June 2016 at 22:05, Henrique C. S. Junior henriquecsj(~)gmail.com < > > owner-chemistry!!ccl.net> wrote: > > > >> Hi, Swetanshu, > >> It is not an easy task to decide what configuration is correct to > >> describe the magnetic couplings in a polynuclear system. The best approa= > ch > >> is to compare the various solutions with an experimental magnetic > >> susceptibility curve using a statistical fit software (like origin). > >> > >> > >> > >> ---------- > >> *Henrique C. S. Junior* > >> Qu=C3=ADmico Industrial - UFRRJ > >> Mestrando em Qu=C3=ADmica Inorg=C3=A2nica - UFRRJ > >> Centro de Processamento de Dados - PMP > >> > >> > >> ------------------------------ > >> > From: owner-chemistry=C3=8Cl.net > >> To: henriquecsjgmail.com > >> Subject: CCL: Coupling constant (Jab) - Why more unpaired electrons mean= > s > >> a smaller coupling? > >> Date: Fri, 24 Jun 2016 11:45:36 +0100 > >> > >> Hi All, > >> > >> I have a question somewhat related to this topic. When working out the J > >> values in a system with more than 3 metal atoms, there are many differen= > t > >> solutions. Each solutions is obtained by choosing a different set of > >> equations. From the above discussion it seems to me that the large > >> differeence in the solutions are due to the large number of unpaired > >> electrons and the reduction in the spacing between levels at higher ener= > gy. > >> Due to this, depending upon the states under consideration the J values > >> obtained would differ (please correct me if I am wrong). But how does on= > e > >> decide as to which set of solution is appropriate. > >> > >> Thanks, > >> Swetanshu. > >> > >> On 12 June 2016 at 00:27, James Buchwald buchwja/rpi.edu < > >> owner-chemistry,ccl.net> wrote: > >> > >> Hi Henrique, > >> > >> The diminishing Jab that you're predicting assumes that (E[HS] - E[BS]) > >> does not grow as quickly as the spin term in the denominator. Depending= > on > >> the system, this is not necessarily the case, and the energy spacing can > >> grow faster. > >> > >> The reason that the equations appear to cause this is that the > >> Heisenberg-Dirac-van Vleck Hamiltonian (which the three equations were > >> derived from) has a "spin ladder" of solutions ranging from the low- spin= > to > >> the high-spin states. If your low-spin state is a singlet, you'll also > >> have triplets, pentets, and so on until you reach the high-spin state. > >> Similarly, if you start from a doublet, you'll have intermediate quartet= > s, > >> etc. > >> > >> As you introduce more and more unpaired electrons, the spin of the > >> high-spin state increases - but all of the intermediate states between t= > he > >> high-spin and low-spin limits still exist. You can work out the splitti= > ng > >> between these individual states in terms of J, and what ends up happenin= > g > >> is that the states spread out. The denominator essentially corrects for > >> that spacing, rather than saying anything about the strength of the > >> magnetic coupling. > >> > >> Best, > >> James > >> > >> On 06/11/2016 05:54 PM, Henrique C. S. Junior henriquecsj-x-gmail.com > >> wrote: > >> > >> I hope this is not a "homework" question, but I'm having a bad time > >> trying to figure this out. > >> Available literature proposes 3 equations to calculate the coupling > >> constant during a Broken-Symmetry approach: > >> > >> J(1) =3D -(E[HS]-E[BS])/Smax**2 > >> J(2) =3D -(E[HS]-E[BS])/(Smax*(Smax+1)) > >> J(3) =3D -(E[HS]-E[BS])/(HS-BS) > >> > >> I'm intrigued by the fact that, from the equations, the more the system > >> have unpaired electrons, the minor will be Jab. Why does this happen? > >> Doesn't more unpaired electrons increase magnetic momenta (and an increa= > se > >> in magnetic coupling)? > >> > >> -- > >> *Henrique C. S. Junior* > >> Qu=C3=ADmico Industrial - UFRRJ > >> Mestrando em Qu=C3=ADmica Inorg=C3=A2nica - UFRRJ > >> Centro de Processamento de Dados - PMP > >> > >> > >> -- > >> James R. Buchwald > >> Doctoral Candidate, Theoretical Chemistry > >> Dinolfo Laboratory > >> Dept. of Chemistry and Chemical Biology > >> Rensselaer Polytechnic Institutehttp://www.rpi.edu/~buchwj > >> > >> > >> > > > > > --=20 > *Henrique C. S. Junior* > Qu=C3=ADmico Industrial - UFRRJ > Mestrando em Qu=C3=ADmica Inorg=C3=A2nica - UFRRJ > Centro de Processamento de Dados - PMP > > --001a113dd29432bd3c053668ae65 > Content-Type: text/html; charset=UTF-8 > Content-Transfer-Encoding: quoted-printable > >
e,monospace">Hi,=C2=A0 s-serif">Swetanshu,
family:monospace,monospace"> al,sans-serif">You don't need the coupling constants before, but you ne= > ed to perform a study to understand what couplings are relevant to your sys= > tem (to figure out how complex the Hamiltonian will be). After you understo= > od your system, you can use, as an example, the software DAVE[1] to see if = > your model fits your experimental data. If not, you have to re-think your s= > ystem and try again to obtain a better fit.
_default" style=3D"font-family:monospace,monospace"> e:12.8px;font-family:arial,sans-serif">
_default"> [1]= > -=C2=A0 .nist.gov/dave/download.html">https://www.ncnr.nist.gov/dave/download.html< = > /a>

ote">2016-06-28 16:53 GMT-03:00 Tandon Swetanshu tandons-,- //tcd.ie">tcd.ie < y.:.ccl.net" target=3D"_blank">owner-chemistry.:.ccl.net>:
ockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #= > ccc solid;padding-left:1ex">
Hi Henrique, >
Thanks a lot for the insight. I have a small doubt. Before obtai= > ning the susceptibility curve, we need to obtain the coupling constant. So = > can't we just compare the calculated coupling constants with the experi= > mental ones?

Thanks again,
Swetanshu.
class=3D"gmail_extra">
On 26 June 2016 at 22:= > 05, Henrique C. S. Junior henriquecsj(~) =3D"_blank">gmail.com < mistry!!ccl.net" target=3D"_blank">owner-chemistry!!ccl.net> = > wrote:
er-left:1px #ccc solid;padding-left:1ex"> > > >
er New, sans-serif">Hi, S= > wetanshu,
pan style=3D"font-size:15px;line-height:21.3px">It is not an easy task to d= > ecide what configuration is correct to describe the magnetic couplings in a= > polynuclear system. The best approach is to compare the various solutions = > with an experimental magnetic susceptibility curve using a statistical fit = > software (like origin).
e-height:21.3px">


-= > ---------
Henri= > que C. S. Junior
New">Qu=C3=ADmico Industrial - UFRRJ
Mestrando em Qu=C3=ADmica Inorg=C3= > =A2nica - UFRRJ
r New">Centro de Processamento de Dados - PMP


= > > From: owner-chemistry=C3=8Cl.net
To: mail.com" target=3D"_blank">henriquecsjgmail.com
Subject: CCL: Coupl= > ing constant (Jab) - Why more unpaired electrons means a smaller coupling?<= > br>Date: Fri, 24 Jun 2016 11:45:36 +0100

Hi All, v>
I have a question somewhat related to this topic. When wor= > king out the J values in a system with more than 3 metal atoms, there are m= > any different solutions.=C2=A0 Each solutions is obtained by choosing a dif= > ferent set of equations. From the above discussion it seems to me that the = > large differeence in the solutions are due to the large number of unpaired = > electrons and the reduction in the spacing between levels at higher energy.= > Due to this, depending upon the states under consideration the J values ob= > tained would differ (please correct me if I am wrong). But how does one dec= > ide as to which set of solution is appropriate.

iv>Thanks,
Swetanshu.

On 12 June 2016 at 00:27= > , James Buchwald buchwja/rpi.e= > du < get=3D"_blank">owner-chemistry,ccl.net> wrote:
style=3D"border-left:1px solid rgb(204,204,204);padding-left:1ex"> > =20 > =20 > =20 >
> Hi Henrique,
>
> The diminishing Jab that you're predicting assumes that (E[HS] - > E[BS]) does not grow as quickly as the spin term in the > denominator.=C2=A0 Depending on the system, this is not necessarily the > case, and the energy spacing can grow faster.
>
> The reason that the equations appear to cause this is that the > Heisenberg-Dirac-van Vleck Hamiltonian (which the three equations > were derived from) has a "spin ladder" of solutions ranging f= > rom the > low-spin to the high-spin states.=C2=A0 If your low-spin state is a > singlet, you'll also have triplets, pentets, and so on until you > reach the high-spin state.=C2=A0 Similarly, if you start from a doublet= > , > you'll have intermediate quartets, etc.
>
> As you introduce more and more unpaired electrons, the spin of the > high-spin state increases - but all of the intermediate states > between the high-spin and low-spin limits still exist.=C2=A0 You can wo= > rk > out the splitting between these individual states in terms of J, and > what ends up happening is that the states spread out.=C2=A0 The > denominator essentially corrects for that spacing, rather than > saying anything about the strength of the magnetic coupling.
>
> Best,
> James
>
>
On 06/11/2016 05:54 PM, Henrique C. S. > Junior h= > enriquecsj-x-gmail.com wrote:
>
>
>
>
>
I > hope this is not a "homework" question, but I'm= > having a > bad time trying to figure this out.
>
Available > literature proposes 3 equations to calculate the coupling > constant during a Broken-Symmetry approach:
>

>
>
J(1) > =3D -(E[HS]-E[BS])/Smax**2
>
J(2) > =3D -(E[HS]-E[BS])/(Smax*(Smax+1))
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J(3) > =3D -(E[HS]-E[BS])/(<S**2>HS-<S**2>BS) v> >

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I'm > intrigued by the fact that, from the equations, the more > the system have unpaired electrons, the minor will be Jab. > Why does this happen? Doesn't more unpaired electrons > increase magnetic momenta (and an increase in magnetic > coupling)?
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<= > font face=3D"monospace, monospace">Henrique C. S= > . Junior
> Qu=C3=ADmico Industrial - UFRRJ
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<= > font face=3D"monospace, monospace">Mestrando em Qu=C3=ADmica > Inorg=C3=A2nica - UFRRJ
> Centro de Processamento de Dados - PMP
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> =3D"#888888"> re>--=20 > James R. Buchwald > Doctoral Candidate, Theoretical Chemistry > Dinolfo Laboratory > Dept. of Chemistry and Chemical Biology > Rensselaer Polytechnic Institute > http://www.rpi.edu= > /~buchwj >
ont color=3D"#888888"> > >
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"monospace, monospace">Mestrando em Qu=C3=ADmica Inorg=C3=A2nica - UFRRJ >Centro de Processamento de Dados - PMP
= >
> > > --001a113dd29432bd3c053668ae65-- > > From owner-chemistry@ccl.net Thu Jun 30 15:49:00 2016 From: "Sharvan Kumar shravan.aug12~!~gmail.com" To: CCL Subject: CCL: Help Regarding NICS-XY scan plot Message-Id: <-52264-160630154741-25352-oZbn+92gvY/JnVCBy2e6ag(~)server.ccl.net> X-Original-From: "Sharvan Kumar" Date: Thu, 30 Jun 2016 15:47:40 -0400 Sent to CCL by: "Sharvan Kumar" [shravan.aug12[-]gmail.com] Dear Sir, I am sharvan, a PhD student from JNU, New Delhi, India. I did the NICS-XY of calculation s-Indacene(DOI: 10.1039/c6sc00950f) and other reported molecules NICS in this paper by aroma software, when I tried to plot it, I have seen the plots are looking same in some what but not exactly matching. The difference is that they have shown + and - value and the highest peaks are at 0, -1 and 1 but I am not finding such. In my case it starts from 0. Please tell me what should I have to do to get the same plot as reported so I can repeat and do the same for my molecule. Thanks regards, Sharvan