From owner-chemistry@ccl.net Fri Jan 24 06:30:00 2014
From: "Marcel Swart marcel.swart[#]icrea.cat" <owner-chemistry,server.ccl.net>
To: CCL
Subject: CCL: negative values in Mulliken spin distribution
Message-Id: <-49604-140124062714-27305-YpXHWVMRq+F54Ur+Cz4CTA,server.ccl.net>
X-Original-From: Marcel Swart <marcel.swart##icrea.cat>
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Date: Fri, 24 Jan 2014 12:27:03 +0100
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Sent to CCL by: Marcel Swart [marcel.swart++icrea.cat]

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Susi,

we=92re saying the same thing, *but* with one big difference.
The probability density you talk about leads to a Mulliken
population analysis, be it the total or separated for spin-up
and spin-down. Like I said, this population analysis is a=20
representation of the charge density, which are (usually)
being assigned to atoms. Whether you take the total charge,
or the difference between alfa- and beta-populations is to
get =93spin-density charges=94 is irrelevant for the concept of
how you get from the density to the atomic populations.
There are many different ways how to get from a charge
density to an atomic population analysis, of which Mulliken
is one choice. But these atomic populations (and hence
the Mulliken (spin) charges) DO directly give a representation
of the charge density; how well it represents it is another issue.
That was my (maybe too subtle) point.

Marcel

On 23 Jan 2014, at 19:27 , Susi Lehtola =
susi.lehtola_._alumni.helsinki.fi <owner-chemistry ~~ ccl.net> wrote:

>> First of all, to set things straight, it is a simplification of the
>> charge density, which are being assigned to atoms. Hence,
>> yes, it is not a real density.
>=20
> No, it is not. You're mixing concepts. Mulliken charges and Mulliken
> spin charges are not the same thing. The first deals with
> electric charge, while the second deals with spin. (Also, I was
> talking about a probability density, which is always non-negative.)
>=20
> In the former you substract electronic charge from the nuclear
> charge to get the net atomic charge. For instance, O in H2O has a
> negative charge due to a relative surplus of electrons. (Here,
> different methods give a variety of different answers, for example
> L=F6wdin can assign O to be positive!)
>=20
> In the latter you substract the amount of spin down electrons from the
> amount of spin up electrons. The value 0 will mean that there are an
> equal amount of spin up and down electrons for the atom. A positive
> value will mean that spin up electrons are in surplus for the atom,
> while a negative value will mean that spin down electrons are in
> surplus.
>=20
> If you calculate a spin polarized system, e.g. the oxygen molecule =
with
> spin multiplicity M=3D3, you'll have a net positive spin charge in the
> system, since you'll have two more spin up electrons than spin down
> electrons. Here, both oxygen atoms will have spin charge +1, although
> the electric charge is 0.
>=20
> On the other hand, even spin neutral systems may have atoms with large
> negative and large positive charges, e.g. in the case of
> antiferromagnetic couplings between atoms.


=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Prof. Dr. Marcel Swart

ICREA Research Professor at
Institut de Qu=EDmica Computacional i Cat=E0lisi
Universitat de Girona

Facultat de Ci=E8ncies
Campus Montilivi
17071 Girona
Catalunya (Spain)

tel
+34-972-418861
fax
+34-972-418356
e-mail
marcel.swart ~~ icrea.cat
marcel.swart ~~ udg.edu
web
http://www.marcelswart.eu

vCard
addressbook://www.marcelswart.eu/MSwart.vcf
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<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html =
charset=3Dwindows-1252"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: =
after-white-space;">Susi,<div><br></div><div>we=92re saying the same =
thing, *but* with one big difference.</div><div>The probability density =
you talk about leads to a Mulliken</div><div>population analysis, be it =
the total or separated for spin-up</div><div>and spin-down. Like I said, =
this population analysis is a&nbsp;</div><div>representation of the =
charge density, which are (usually)</div><div>being assigned to atoms. =
Whether you take the total charge,</div><div>or the difference between =
alfa- and beta-populations is to</div><div>get =93spin-density charges=94 =
is irrelevant for the concept of</div><div>how you get from the density =
to the atomic populations.</div><div>There are many different ways how =
to get from a charge</div><div>density to an atomic population analysis, =
of which Mulliken</div><div>is one choice. But these atomic populations =
(and hence</div><div>the Mulliken (spin) charges) DO directly give a =
representation</div><div>of the charge density; how well it represents =
it is another issue.</div><div>That was my (maybe too subtle) =
point.</div><div><br></div><div>Marcel</div><div><br><div><div>On 23 Jan =
2014, at 19:27 , Susi Lehtola susi.lehtola_._<a =
href=3D"http://alumni.helsinki.fi">alumni.helsinki.fi</a> &lt;<a =
href=3D"mailto:owner-chemistry ~~ ccl.net">owner-chemistry ~~ ccl.net</a>&gt; =
wrote:</div><br class=3D"Apple-interchange-newline"><blockquote =
type=3D"cite"><blockquote type=3D"cite">First of all, to set things =
straight, it is a simplification of the<br>charge density, which are =
being assigned to atoms. Hence,<br>yes, it is not a real =
density.<br></blockquote><br>No, it is not. You're mixing concepts. =
Mulliken charges and Mulliken<br>spin charges are not the same thing. =
The first deals with<br>electric charge, while the second deals with =
spin. (Also, I was<br>talking about a probability density, which is =
always non-negative.)<br><br>In the former you substract electronic =
charge from the nuclear<br>charge to get the net atomic charge. For =
instance, O in H2O has a<br>negative charge due to a relative surplus of =
electrons. (Here,<br>different methods give a variety of different =
answers, for example<br>L=F6wdin can assign O to be positive!)<br><br>In =
the latter you substract the amount of spin down electrons from =
the<br>amount of spin up electrons. The value 0 will mean that there are =
an<br>equal amount of spin up and down electrons for the atom. A =
positive<br>value will mean that spin up electrons are in surplus for =
the atom,<br>while a negative value will mean that spin down electrons =
are in<br>surplus.<br><br>If you calculate a spin polarized system, e.g. =
the oxygen molecule with<br>spin multiplicity M=3D3, you'll have a net =
positive spin charge in the<br>system, since you'll have two more spin =
up electrons than spin down<br>electrons. Here, both oxygen atoms will =
have spin charge +1, although<br>the electric charge is 0.<br><br>On the =
other hand, even spin neutral systems may have atoms with =
large<br>negative and large positive charges, e.g. in the case =
of<br>antiferromagnetic couplings between =
atoms.<br></blockquote></div><br><div apple-content-edited=3D"true">
<div style=3D"color: rgb(0, 0, 0); font-family: Helvetica;  font-style: =
normal; font-variant: normal; font-weight: normal; letter-spacing: =
normal; line-height: normal; orphans: 2; text-align: -webkit-auto; =
text-indent: 0px; text-transform: none; white-space: normal; widows: 2; =
word-spacing: 0px; -webkit-text-size-adjust: auto; =
-webkit-text-stroke-width: 0px; word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span =
class=3D"Apple-style-span" style=3D"border-collapse: separate; =
border-spacing: 0px;"><div style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span =
class=3D"Apple-style-span" style=3D"border-collapse: separate; color: =
rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: =
normal; font-weight: normal; letter-spacing: normal; line-height: =
normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; =
text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; =
border-spacing: 0px; -webkit-text-decorations-in-effect: none; =
-webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;  "><div =
style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space; "><br =
class=3D"Apple-interchange-newline">=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D<br>Prof=
. Dr. Marcel Swart<br><br>ICREA Research Professor at<br>Institut de =
Qu=EDmica Computacional i Cat=E0lisi<br>Universitat de =
Girona<br><br>Facultat de Ci=E8ncies<br>Campus Montilivi</div><div =
style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space; ">17071 Girona</div><div =
style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space; ">Catalunya =
(Spain)<br><br>tel<br>+34-972-418861<br>fax<br>+34-972-418356<br>e-mail<br=
><a =
href=3D"mailto:marcel.swart ~~ icrea.cat">marcel.swart ~~ icrea.cat</a><br>marce=
l.swart ~~ udg.edu<br>web<br>http://www.marcelswart.eu</div><div =
style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space; "><br></div><div =
style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space; ">vCard<br><a =
href=3D"addressbook://www.marcelswart.eu/MSwart.vcf">addressbook://www.mar=
celswart.eu/MSwart.vcf</a><br>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D<br></div></sp=
an></div></span></div>
</div>
<br></div></body></html>=

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From owner-chemistry@ccl.net Fri Jan 24 11:58:00 2014
From: "Fedor Goumans goumans%x%scm.com" <owner-chemistry~~server.ccl.net>
To: CCL
Subject: CCL: ADF in HPC
Message-Id: <-49605-140124033202-28816-iDwhpjLhhjG4vdjdCiWwBw~~server.ccl.net>
X-Original-From: Fedor Goumans <goumans%%scm.com>
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Date: Fri, 24 Jan 2014 09:31:45 +0100
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Sent to CCL by: Fedor Goumans [goumans]=[scm.com]
Dear May Abdelghani,

Are you looking for ADF on French HPC centers?
CINES: http://www.cines.fr/spip.php?article855&lang=fr
IDRIS: http://www.idris.fr/ada/logiciels/ada-adf.html

Best wishes,
Fedor

On 1/23/2014 10:22 PM, may abdelghani may01dz]~[yahoo.fr wrote:
> Sent to CCL by: "may  abdelghani" [may01dz.:.yahoo.fr]
> Dear CCL'ers
> I look for a high-performance computing  clusters  that contains the Amsterdam density functional (ADF)  program
> thanks>
>


-- 
Dr. T. P. M. (Fedor) Goumans
Business Developer
Scientific Computing & Modelling NV (SCM)
Vrije Universiteit, FEW, Theoretical Chemistry
De Boelelaan 1083
1081 HV Amsterdam, The Netherlands
T +31 20 598 7625
F +31 20 598 7629
E-mail: goumans .. scm.com
http://www.scm.com