From owner-chemistry@ccl.net Fri Nov 29 08:06:01 2013
From: "Sergio Manzetti sergio.manzetti%x%gmx.com" =C2=A0
1. One Table salt molecu=
le.
2. One Sodium atom and one Chloride atom next to each other,=
spaced by 1.2 =C3=85.
Sergio----- Orig=
inal Message -----
= From: La= urence Cuffe cuffe(~)mac.com
Sent: 11/28/13 10:29 PM
T= o: Manzetti, Sergio
Subject: CCL:G: Earth metal oxides in Gaussian
=C2=A0Sent from QCloud
Sent to CC= L by: "Sergio Manzetti" [sergio.manzetti(a)gmx.com]
Dear all, as earth= metal oxides, such as ZnO are particles, how can these be represented corr= ectly as single molecules for calculations? Considering their charge, for i= nstance, Mg2+ and O2-, their bonding should be ionic, however this is not c= learly represented in the gaussian outputs when running simple MgO calculat= ions and Mg can assimilate multiple bonds to other neighbouring atoms.
How can this be correctly defined? Should open shell calculations be= used?
Thanks
=C2=A0
--========GMXBoundary208791385716574266531-- From owner-chemistry@ccl.net Fri Nov 29 09:53:00 2013 From: "Herbert Fruchtl herbert.fruchtl!A!st-andrews.ac.uk"style=3D3D"margin:0px;=3D > padding:0px;" >=3DC2=3DA0
#CCC;=3D > padding-left: 5px; margin-left: 5px; margin-bottom: 0px; margin-top: 0px= ; > =3D > margin-right: 0px;" type=3D3D"cite">>
pan style=3D3D"font-family:Verdana">----= - > Orig=3D > inal Message -----
>=3D > Fr= om: > La=3D > urence Cuffe cuffe(~)mac.com
paddi=3D > ng:0px;" > style=3D3D"font-size:12px=3D > ">Sent: 11/28/13 10:29 PM
padding:=3D > 0px;" > style=3D3D"font-size:12px">T=3D > o: Manzetti, Sergio
ng:0px;" > style=3D3D"font-size:12px=3D > ">Subject: CCL:G: Earth metal oxides in > Gaussian
=3DC2=3DA0bre=3D > ak-word; font-size:11;font-family: 'Helvetica Neue', Helvetica, > sans-serif;=3D > font-size: 15px; white-space: pre-wrap">Sent from > QCloud
=3D > padding:0px;" >=3DC2=3DA0
How does one distingusih from a calculation = of:
1. One Table salt molecule.
2. One Sodium atom and one Chloride atom next to each other, spaced by 1.2 = =C5.
Sergio
----- Original Message -----Laurence Cuffethe strange characters on the top line to the ]^[ sign.= You can alsoE-mail to subscribers: =A0CHEMISTRY%5D%5E%5Bccl.net =A0or use:= E-mail to administrators: =A0CHEMISTRY-REQUEST%5D%5E%5Bccl.net =A0or usehtt= p://www.ccl.net/chemistry/sub_unsub.shtmlhttp:/= /www.ccl.net/spammers.txt--=3D=3D=3D=3D=3D=3D=3D=3DGMXBoundary2087913857165= 74266531
> From: Laurence Cuffe cuffe(~)mac.com
Sent: 11/28/13 10:29 PM
To: Manzetti, Sergio
Subject: CCL:G: Earth metal oxides in Gaussian
Sent from QCloud
On Nov 28, 2013, at 05:03 AM, "Sergio Manzetti sergio.manzetti:gmx.com" <owner-chemistry= ]^[ccl.net> wrote:
Sent to CCL by: "Sergio Manzetti" [sergio.manzetti(a)gmx.com]
Dear all, as earth metal oxides, such as ZnO are particles, how can these b= e represented correctly as single molecules for calculations? Considering t= heir charge, for instance, Mg2+ and O2-, their bonding should be ionic, how= ever this is not clearly represented in the gaussian outputs when running s= imple MgO calculations and Mg can assimilate multiple bonds to other neighb= ouring atoms.
How can this be correctly defined? Should open shell calculations be used?<= br>
Thanks
There is a bit of a culture and language issue here. We are taught all sort= s of models of bonding and electron behavior in our chemical education, and= it is sometimes dificult to realise that an electronic structure model, as= implemented by an ab initio program such as the one you mentioned, is a de= eper model where the language of interation which we inherit from the simpl= er descriptions, may no longer be the most acurate way of describing what i= s happening. By all means try open shell calculations, but be prepared for = the eventuality that they may not clarify the picture in terms of a simpler= understanding.
All the best
Content-Type: text/html; charset=3D"utf-8"
Content-Transfer-Encoding: quoted-printable
<span style=3D3D'font-family:Verdana'><span style=3D3D'= ;font-size:12px'>How does=3D
=A0one distingusih from a calculation of:<br /><br />1. One Tab= le salt molecu=3D
le.<br /><br />2. One Sodium atom and one Chloride atom next to= each other,=3D
=A0spaced by 1.2 =3DC3=3D85.<br /><br /><br /><br />= ;Sergio<p style=3D3D"margin:0px;=3D
=A0padding:0px;" >=3DC2=3DA0</p><blockquote style=3D3D&quo= t;border-left: 1px solid #CCC;=3D
=A0padding-left: 5px; margin-left: 5px; margin-bottom: 0px; margin-top: 0px= ; =3D
margin-right: 0px;" type=3D3D"cite"><p style=3D3D"= ;margin:0px; padding:0px;" ><s=3D
pan style=3D3D"font-family:Verdana"><span style=3D3D"f= ont-size:12px">----- Orig=3D
inal Message -----</span></span></p><p style=3D3D"= ;margin:0px; padding:0px;" >=3D
<span style=3D3D"font-family:Verdana"><span style=3D3D&q= uot;font-size:12px">From: La=3D
urence Cuffe cuffe(~)mac.com= a></span></span></p><p style=3D3D"margin:0px; pad= di=3D
ng:0px;" ><span style=3D3D"font-family:Verdana"><= ;span style=3D3D"font-size:12px=3D
">Sent: 11/28/13 10:29 PM</span></span></p><p = style=3D3D"margin:0px; padding:=3D
0px;" ><span style=3D3D"font-family:Verdana"><sp= an style=3D3D"font-size:12px">T=3D
o: Manzetti, Sergio </span></span></p><p style=3D3D&qu= ot;margin:0px; paddi=3D
ng:0px;" ><span style=3D3D"font-family:Verdana"><= ;span style=3D3D"font-size:12px=3D
">Subject: CCL:G: Earth metal oxides in Gaussian</span></s= pan></p>=3DC2=3DA0<di=3D
v><div>=3DC2=3DA0</div><div><pre style=3D3D"wh= ite-space: pre-wrap; word-wrap: bre=3D
ak-word; font-size:11;font-family: 'Helvetica Neue', Helvetica, san= s-serif;=3D
=A0font-size: 15px; white-space: pre-wrap">Sent from QCloud</pre= ></div><div><=3D
br />On Nov 28, 2013, at 05:03 AM, "Sergio Manzetti sergio.manzetti= :gmx.com=3D
" <owner-chemistry]^[ccl.net> wrote:<br />=3DC2=3DA0<div><blockquot= e type=3D
=3D3D"cite"><div class=3D3D"msg-quote"><div= class=3D3D"_stretch"><br />Sent to CC=3D
L by: "Sergio Manzetti" [sergio.manzetti(a)gmx.com]<br />Dear all, as earth=3D
=A0metal oxides, such as ZnO are particles, how can these be represented co= rr=3D
ectly as single molecules for calculations? Considering their charge, for i= =3D
nstance, Mg2+ and O2-, their bonding should be ionic, however this is not c= =3D
learly represented in the gaussian outputs when running simple MgO calculat= =3D
ions and Mg can assimilate multiple bonds to other neighbouring atoms.<b= r /=3D
><br />How can this be correctly defined? Should open shell calcul= ations be=3D
=A0used?<br /><br />Thanks</div></div></blockquo= te><span> </span><br />T=3D
here is a bit of a culture and language issue here. We are taught all sorts= =3D
=A0of models of bonding and electron behavior in our chemical education, an= d =3D
it is sometimes dificult to realise that an electronic structure model, as = =3D
implemented by an ab initio program such as the one you mentioned, is a dee= =3D
per model where the language of interation which we inherit from the simple= =3D
r descriptions, may no longer be the most acurate way of describing what is= =3D
=A0happening. By all means try open shell calculations, but be prepared for= t=3D
he eventuality that they may not clarify the picture in terms of a simpler = =3D
understanding.<br />All the best<br />Laurence Cuffe<br />= ;<br />=3DC2=3DA0<bloc=3D
kquote type=3D3D"cite"><div class=3D3D"msg-quote"= ><div class=3D3D"_stretch"><br /=3D
><br /><br />-=3D3D This is automatically added to each mess= age by the mailin=3D
g script =3D3D-<br />To recover the email address of the author of th= e messag=3D
e, please change<br />the strange characters on the top line to the ]= ^[ sig=3D
n. You can also<br /<=3D
br /><br />E-mail to subscribers: <a href=3D3D"mailto:CHEMISTRY%5D%5E%5Bccl.n=3D=
et">CHEMISTRY]^[ccl.ne= t</a> or use:<br /><a href=3D3D"http://www.ccl.net/cgi-=3D
bin/ccl/send_ccl_message">http://www.ccl.net/cgi-bin/ccl/sen= d_ccl_message</=3D
a><br /><br />E-mail to administrators: <a href=3D3D"= ;mailto:CHEMISTRY-REQUEST=3D
%5D%5E%5Bccl.net">CHEMISTRY-REQUEST]^[ccl.net</a> or use<br /><a href=3D3D&quo= t;ht=3D
tp://www.ccl.net/cgi-bin/ccl/send_ccl_message">http://www.ccl.net/cgi-bin/c=3D
cl/send_ccl_message</a><br /><br />Subscribe/Unsubscr= ibe:<br /><a href=3D3D"h=3D
ttp://www.ccl.net/chemistry/sub_unsub.shtml">http://www.ccl.net/chemistry/s=3D
ub_unsub.shtml</a><br /><br />Before posting, check w= ait time at: <a href=3D
=3D3D"http://www.ccl.= net">http://ww= w.ccl.net</a><br /><br />Job: <a href=3D3D"h= =3D
ttp://www.ccl.net/job= s">http:/= /www.ccl.net/jobs</a><br />Conferences: <a hr=3D
ef=3D3D"http://server.ccl.net/chemistry/announcements/co= nferences/">http://se= a>=3D
rver.ccl.net/chemistry/announcements/conferences/</a>= <br /><br />Search Mes=3D
sages: <a href=3D3D"http://www.ccl.net/chemistry/searchccl/in= dex.shtml">http:=3D
//www.ccl.net/chemistry/searchccl/index.shtml</a><br /&g= t;<br /><a href=3D3D"htt=3D
p://www.ccl.n= et/spammers.txt">http://www.ccl.net/spammers.txt</a><br />&l= t;br =3D
/>RTFI: <a href=3D3D"http://www.ccl.net/chemistry/aboutcc= l/instructions/">htt=3D
p://www.ccl.net/chemistry/aboutccl/instructions/</a><b= r /><br />=3DC2=3DA0</div=3D
></div></blockquote></div></div></div><= /blockquote><p style=3D3D"margin:0px; =3D
padding:0px;" >=3DC2=3DA0</p></span></span>
=C2=A0
----- Original Message -----
From: Herbert Fruchtl herbert.fruchtl!A!st-andrews.ac.uk
Sent: 11/29/13 02:16 PM<= /p>
To: Manzetti, Sergio
Subject: CCL:G: Earth metal oxides in = Gaussian
=C2=A0=Sent to CCL by: Herbert Frucht= l [herbert.fruchtl|-|st-andrews.ac.uk]=20 There are two questions here: How do you treat mineral particles theoretica= lly,=20 and how do you find out things like ionicity and bond order from quantum=20 mechanical calculations?=20 For the first question: A molecule of MgO in the gas phase (if that exists)= is=20 different from the solid. You don't say how large the particles are that yo= u=20 want to treat, but if you are using the cluster approach with a program lik= e=20 Gaussian, you are limited to a few tens of atoms. There is debate as to whe= n the=20 properties of a cluster of atoms or molecules become bulk-like. Some people= take=20 the opposite approach of treating solids as infinite crystals, and surfaces= as=20 periodic thin slabs of a few layers of atoms, which is of course also an=20 approximation that may or may not be good if you look at nanoparticles or r= ough=20 surfaces. You need to know what you want to describe, which properties you = want=20 to determine, and what approximations are acceptable.=20 To the second question: ab initio or DFT calculations give you a wavefuncti= on or=20 charge density of a number of electrons in the field of nuclei or cores. Bo= nds,=20 atoms, ions, etc. are interpretations of this. There are theories that give= you=20 numbers, and holy wars are being fought between the adherents of different= =20 theories. If you use Gaussian, NBO is a reasonable first approximation. Mul= liken=20 isn't, particularly if you use diffuse basis functions. QTAIM (for which yo= u=20 need a different program) is the most intuitive for atomic charges, but not= =20 everybody will agree with this statement.=20 Good luck,=20 Herbert=20 On 28/11/13 13:03, Sergio Manzetti sergio.manzetti:gmx.com wrote:=20 >=20 > Sent to CCL by: "Sergio Manzetti" [sergio.manzetti(a)gmx.com]=20 > Dear all, as earth metal oxides, such as ZnO are particles, how can th= ese be represented correctly as single molecules for calculations? Consider= ing their charge, for instance, Mg2+ and O2-, their bonding should be ionic= , however this is not clearly represented in the gaussian outputs when runn= ing simple MgO calculations and Mg can assimilate multiple bonds to other n= eighbouring atoms.=20 >=20 > How can this be correctly defined? Should open shell calculations be u= sed?=20 >=20 > Thanks>=20 >=20 --=20 Herbert Fruchtl=20 Senior Scientific Computing Officer=20 School of Chemistry, School of Mathematics and Statistics=20 University of St Andrews=20 --=20 The University of St Andrews is a charity registered in Scotland:=20 No SC013532=20 -=3D This is automatically added to each message by the mailing script =3D-= =20=20=20=20=20=20=20=20 Subscribe/Unsubscribe:=20=20=20 Job: http://www.ccl.net/jobs=20=20=20=20=20
=C2=A0
=C2=A0
----- Orig= inal Message -----
= From: La= urence Cuffe cuffe(~)http://mac.com
Sent: 11/28/13 10:29 PM
T= o: Manzetti, Sergio
Subject: CCL:G: Earth metal oxides in Gaussian
=C2=A0Sent from QCloud
Sent to CC= L by: "Sergio Manzetti" [sergio.manzetti(a)http://gmx.com ]
Dear all, as earth= metal oxides, such as ZnO are particles, how can these be represented corr= ectly as single molecules for calculations? Considering their charge, for i= nstance, Mg2+ and O2-, their bonding should be ionic, however this is not c= learly represented in the gaussian outputs when running simple MgO calculat= ions and Mg can assimilate multiple bonds to other neighbouring atoms.
How can this be correctly defined? Should open shell calculations be= used?
Thanks
=C2=A0
=C2=A0
----- Original Message -----<= /p>
From: Brian Skinn brian.skinn---gmail.com=
Sent: 11/29/13 03:15 PM
To: Manzetti, Sergio =
Subject: CCL:G: Earth meta= l oxides in Gaussian
=C2=A0How does one distingusih from a calculation of:
1. One Table= salt molecule.
2. One Sodium atom and one Chloride atom next to= each other, spaced by 1.2 =C3=85.
Sergio----- Original Message -----Laurence Cuffethe strange characters on the top line= to the ]^[ sign. You can alsoE-mail to subscribers: CHEMISTRY%5D%5E%= 5Bccl.net or use:E-mail to administrators: CHEMISTRY-REQUEST%5D= %5E%5Bccl.net or usehttp://www.ccl.net= /chemistry/sub_unsub.shtmlhttp://www.ccl.net/spammers.txt--=3D=3D=3D=3D=3D= =3D=3D=3DGMXBoundary208791385716574266531
> From: Laurence Cuffe cuffe(~= )mac.com
Sent: 11/28/= 13 10:29 PM
To: Manzetti, Sergio
Subject: CCL:G: Earth metal oxid= es in Gaussian
Sent from QCloud
On Nov 28, 2013, at 05:03 A= M, "Sergio Manzetti sergio.manzetti:gmx.com" <owner-chemistry]^[ccl.net> wrote:
Sent to CCL by: "Sergio Manzet= ti" [sergio.manzetti(a)gmx.com= ]
Dear all, as earth metal oxides, such as ZnO are particles, how = can these be represented correctly as single molecules for calculations? Co= nsidering their charge, for instance, Mg2+ and O2-, their bonding should be= ionic, however this is not clearly represented in the gaussian outputs whe= n running simple MgO calculations and Mg can assimilate multiple bonds to o= ther neighbouring atoms.
How can this be correctly defined? Shou= ld open shell calculations be used?
Thanks
There is a bit o= f a culture and language issue here. We are taught all sorts of models of b= onding and electron behavior in our chemical education, and it is sometimes= dificult to realise that an electronic structure model, as implemented by = an ab initio program such as the one you mentioned, is a deeper model where= the language of interation which we inherit from the simpler descriptions,= may no longer be the most acurate way of describing what is happening. By = all means try open shell calculations, but be prepared for the eventuality = that they may not clarify the picture in terms of a simpler understanding.<= br />All the best
Content-Type: text/html;= charset=3D"utf-8"
Content-Transfer-Encoding: quoted-printable
<span style=3D3D'font-family:Verdana'><span style=3D3D'font-si= ze:12px'>How does=3D
one distingusih from a calculation of:&l= t;br /><br />1. One Table salt molecu=3D
le.<br /><b= r />2. One Sodium atom and one Chloride atom next to each other,=3D
spaced by 1.2 =3DC3=3D85.<br /><br /><br /><br = />Sergio<p style=3D3D"margin:0px;=3D
padding:0px;" >=3D= C2=3DA0</p><blockquote style=3D3D"border-left: 1px solid #CCC;=3D<= br /> padding-left: 5px; margin-left: 5px; margin-bottom: 0px; margin-= top: 0px; =3D
margin-right: 0px;" type=3D3D"cite"><p style=3D3D"= margin:0px; padding:0px;" ><s=3D
pan style=3D3D"font-family:Verd= ana"><span style=3D3D"font-size:12px">----- Orig=3D
inal Mess= age -----</span></span></p><p style=3D3D"margin:0px; p= adding:0px;" >=3D
<span style=3D3D"font-family:Verdana"><s= pan style=3D3D"font-size:12px">From: La=3D
urence Cuffe cuffe(~)mac.com</span></span= ></p><p style=3D3D"margin:0px; paddi=3D
ng:0px;" ><s= pan style=3D3D"font-family:Verdana"><span style=3D3D"font-size:12px= =3D
">Sent: 11/28/13 10:29 PM</span></span></p>&l= t;p style=3D3D"margin:0px; padding:=3D
0px;" ><span style=3D3D"f= ont-family:Verdana"><span style=3D3D"font-size:12px">T=3D
o: = Manzetti, Sergio </span></span></p><p style=3D3D"margi= n:0px; paddi=3D
ng:0px;" ><span style=3D3D"font-family:Verdana"&= gt;<span style=3D3D"font-size:12px=3D
">Subject: CCL:G: Earth me= tal oxides in Gaussian</span></span></p>=3DC2=3DA0<di= =3D
v><div>=3DC2=3DA0</div><div><pre style=3D3= D"white-space: pre-wrap; word-wrap: bre=3D
ak-word; font-size:11;font-= family: 'Helvetica Neue', Helvetica, sans-serif;=3D
font-size: 1= 5px; white-space: pre-wrap">Sent from QCloud</pre></div><= div><=3D
br />On Nov 28, 2013, at 05:03 AM, "Sergio Manzetti = sergio.manzetti:gmx.com=3D=
" <owner-chemistry]^[ccl.net> wrote:<br />=3DC2=3DA0<div><blockquo= te type=3D
=3D3D"cite"><div class=3D3D"msg-quote"><div cla= ss=3D3D"_stretch"><br />Sent to CC=3D
L by: "Sergio Manzetti"= [sergio.manzetti(a)gmx.com]<br />Dear all, as earth=3D
metal oxides, such as ZnO ar= e particles, how can these be represented corr=3D
ectly as single mole= cules for calculations? Considering their charge, for i=3D
nstance, Mg= 2+ and O2-, their bonding should be ionic, however this is not c=3D
le= arly represented in the gaussian outputs when running simple MgO calculat= =3D
ions and Mg can assimilate multiple bonds to other neighbouring at= oms.<br /=3D
><br />How can this be correctly defined? Sho= uld open shell calculations be=3D
used?<br /><br />T= hanks</div></div></blockquote><span> </= span><br />T=3D
here is a bit of a culture and language issue= here. We are taught all sorts=3D
of models of bonding and elect= ron behavior in our chemical education, and =3D
it is sometimes dificu= lt to realise that an electronic structure model, as =3D
implemented b= y an ab initio program such as the one you mentioned, is a dee=3D
per = model where the language of interation which we inherit from the simple=3D<= br />r descriptions, may no longer be the most acurate way of describing wh= at is=3D
happening. By all means try open shell calculations, bu= t be prepared for t=3D
he eventuality that they may not clarify the pi= cture in terms of a simpler =3D
understanding.<br />All the best= <br />Laurence Cuffe<br /><br />=3DC2=3DA0<bloc=3D
kquote type=3D3D"cite"><div class=3D3D"msg-quote"><div class= =3D3D"_stretch"><br /=3D
><br /><br />-=3D3D This= is automatically added to each message by the mailin=3D
g script =3D3= D-<br />To recover the email address of the author of the messag=3De, please change<br />the strange characters on the top line to t= he ]^[ sig=3D
n. You can also<br /<=3D
br /><br />= E-mail to subscribers: <a href=3D3D"mailto:CHEMISTRY%5D%5E%5Bccl.n=3D
et">CHEMISTRY]^[= ccl.net</a> or use:&= lt;br /><a href=3D3D"http://www.ccl.net/cgi-=3D
bin/ccl= /send_ccl_message">http://www.ccl.net/cgi-bin/ccl/send_ccl_messag= e</=3D
a><br /><br />E-mail to administrators: &= lt;a href=3D3D"mailto:CHEMISTRY-REQUES= T=3D
%5D%5E%5Bccl.net">CHEMISTRY-REQUEST]^[ccl.net</a> or use<br /><a href= =3D3D"ht=3D
tp://www.ccl.net/cgi-bin/ccl/send_ccl_message"><= a target=3D"_blank" href=3D"http://www.ccl.net/cgi-bin/c=3D%0Acl/send_ccl_m= essage">http://www.ccl.net/cgi-bin/c=3D
cl/send_ccl_message</a&= gt;<br /><br />Subscribe/Unsubscribe:<br /><a href=3D3= D"h=3D
ttp://www.ccl.net/chemistry/sub_unsub.shtml">htt= p://www.ccl.net/chemistry/s=3D
ub_unsub.shtml</a><br />= ;<br />Before posting, check wait time at: <a href=3D
=3D3D"<= a target=3D"_blank" href=3D"http://www.ccl.net">http://www.ccl.net">= http://www.ccl.net<= /a><br /><br />Job: <a href=3D3D"h=3D
ttp://www.ccl.net/jobs">http://www.ccl.net/jobs= a></a><br />Conferences: <a hr=3D
ef=3D3D"http://server.ccl.net/chemistry/announcements/conferences/">http://se=3D
rver.ccl= .net/chemistry/announcements/conferences/</a><br /><br /= >Search Mes=3D
sages: <a href=3D3D"http://www.ccl.net/chem= istry/searchccl/index.shtml">http:=3D
//www.ccl.net/chemi= stry/searchccl/index.shtml</a><br /><br /><a href= =3D3D"htt=3D
p://www.ccl.net/spammers.txt">http://www.ccl.net/spammers.txt</a>&= lt;br /><br =3D
/>RTFI: <a href=3D3D"http://www.ccl= .net/chemistry/aboutccl/instructions/">htt=3D
p://www.cc= l.net/chemistry/aboutccl/instructions/</a><br /><br />= ;=3DC2=3DA0</div=3D
></div></blockquote></div>= </div></div></blockquote><p style=3D3D"margin:0px; =3D=
padding:0px;" >=3DC2=3DA0</p></span></span>
=C2=A0
padding:0px;" >=3DC2=3DA0
padding-left: 5px; margin-left: 5px; margin-bottom: 0px; margin-top: = 0px; =3D > margin-right: 0px;" type=3D3D"cite">
pan style=3D3D"font-family:Verdana">----- Orig=3D > inal Message -----
=3D > From: La=3D > urence Cuffe cuffe(~)mac.com
ng:0px;" > ">Sent: 11/28/13 10:29 PM
0px;" >T=3D > o: Manzetti, Sergio
ng:0px;" > ">Subject: CCL:G: Earth metal oxides in = Gaussian
=3DC2=3DA0ak-word; font-size:11;font-family: 'Helvetica Neue', Helvetica, = sans-serif;=3D > font-size: 15px; white-space: pre-wrap">Sent from = QCloud
padding:0px;" >=3DC2=3DA0
Gas phase simulations of crystal unit cells do not, = in general, represent a good model for the extended phase properties of = that crystal. If I'm understanding what you're seeking to = investigate, you should probably consider something more like CPMD or = CASINO (quantum Monte Carlo), using an infinitely repeating simulation = box. These should allow more ready examination of the extended = system of, e.g., your MgO particle or the surface of that particle, and = also of the various geometrical configurations/microstates accessible to = that system at your temperature of interest.Or:3) One Na atom = next to a Cl atom in a three-dimensional matrix of Na and Cl = atoms.
-BrianOn Fri, Nov 29, 2013 at 4:16 AM, Sergio Manzetti = sergio.manzetti%x%gmx.com <owner-chemistry=CCl.net> wrote:
How does one = distingusih from a calculation of:
1. One Table salt molecule.
2. One Sodium atom and one Chloride atom next to each other, spaced by = 1.2 =C5.
Sergio
----- Original Message -----Laurence Cuffethe strange characters on the top line to the ]^[ = sign. You can alsoE-mail to subscribers: CHEMISTRY%5D%5E%5Bccl.net or use:E-mail to = administrators: CHEMISTRY-REQUEST%5D%5E%5Bccl.net or usehttp://www.ccl.net/chemistry/sub_unsub.shtmlhttp://www.ccl.net/= spammers.txt--=3D=3D=3D=3D=3D=3D=3D=3DGMXBoundary208791385716574266531
> From: Laurence Cuffe cuffe(~)mac.com
Sent: 11/28/13 10:29 PM
To: Manzetti, Sergio
Subject: CCL:G: Earth metal oxides in Gaussian
Sent from QCloud
On Nov 28, 2013, at 05:03 AM, "Sergio Manzetti sergio.manzetti:gmx.com" = <owner-chemistry]^[ccl.net> wrote:
Sent to CCL by: "Sergio Manzetti" [sergio.manzetti(a)gmx.com]
Dear all, as earth metal oxides, such as ZnO are particles, how can = these be represented correctly as single molecules for calculations? = Considering their charge, for instance, Mg2+ and O2-, their bonding = should be ionic, however this is not clearly represented in the gaussian = outputs when running simple MgO calculations and Mg can assimilate = multiple bonds to other neighbouring atoms.
How can this be correctly defined? Should open shell calculations be = used?
Thanks
There is a bit of a culture and language issue here. We are taught all = sorts of models of bonding and electron behavior in our chemical = education, and it is sometimes dificult to realise that an electronic = structure model, as implemented by an ab initio program such as the one = you mentioned, is a deeper model where the language of interation which = we inherit from the simpler descriptions, may no longer be the most = acurate way of describing what is happening. By all means try open shell = calculations, but be prepared for the eventuality that they may not = clarify the picture in terms of a simpler understanding.
All the best
= Content-Type: text/html; charset=3D"utf-8"
Content-Transfer-Encoding: quoted-printable
<span style=3D3D'font-family:Verdana'><span = style=3D3D'font-size:12px'>How does=3D
one distingusih from a calculation of:<br /><br />1. = One Table salt molecu=3D
le.<br /><br />2. One Sodium atom and one Chloride atom next = to each other,=3D
spaced by 1.2 =3DC3=3D85.<br /><br /><br = /><br />Sergio<p style=3D3D"margin:0px;=3D
padding:0px;" >=3DC2=3DA0</p><blockquote = style=3D3D"border-left: 1px solid #CCC;=3D
padding-left: 5px; margin-left: 5px; margin-bottom: 0px; = margin-top: 0px; =3D
margin-right: 0px;" type=3D3D"cite"><p style=3D3D"margin:0px; = padding:0px;" ><s=3D
pan style=3D3D"font-family:Verdana"><span = style=3D3D"font-size:12px">----- Orig=3D
inal Message -----</span></span></p><p = style=3D3D"margin:0px; padding:0px;" >=3D
<span style=3D3D"font-family:Verdana"><span = style=3D3D"font-size:12px">From: La=3D
urence Cuffe cuffe(~)mac.com</span></span></p><p = style=3D3D"margin:0px; paddi=3D
ng:0px;" ><span style=3D3D"font-family:Verdana"><span = style=3D3D"font-size:12px=3D
">Sent: 11/28/13 10:29 PM</span></span></p><p = style=3D3D"margin:0px; padding:=3D
0px;" ><span style=3D3D"font-family:Verdana"><span = style=3D3D"font-size:12px">T=3D
o: Manzetti, Sergio </span></span></p><p = style=3D3D"margin:0px; paddi=3D
ng:0px;" ><span style=3D3D"font-family:Verdana"><span = style=3D3D"font-size:12px=3D
">Subject: CCL:G: Earth metal oxides in = Gaussian</span></span></p>=3DC2=3DA0<di=3D
v><div>=3DC2=3DA0</div><div><pre = style=3D3D"white-space: pre-wrap; word-wrap: bre=3D
ak-word; font-size:11;font-family: 'Helvetica Neue', Helvetica, = sans-serif;=3D
font-size: 15px; white-space: pre-wrap">Sent from = QCloud</pre></div><div><=3D
br />On Nov 28, 2013, at 05:03 AM, "Sergio Manzetti = sergio.manzetti:gmx.com=3D
" <owner-chemistry]^[ccl.net> wrote:<br = />=3DC2=3DA0<div><blockquote type=3D
=3D3D"cite"><div class=3D3D"msg-quote"><div = class=3D3D"_stretch"><br />Sent to CC=3D
L by: "Sergio Manzetti" [sergio.manzetti(a)gmx.com]<br />Dear all, as earth=3D
metal oxides, such as ZnO are particles, how can these be = represented corr=3D
ectly as single molecules for calculations? Considering their charge, = for i=3D
nstance, Mg2+ and O2-, their bonding should be ionic, however this is = not c=3D
learly represented in the gaussian outputs when running simple MgO = calculat=3D
ions and Mg can assimilate multiple bonds to other neighbouring = atoms.<br /=3D
><br />How can this be correctly defined? Should open shell = calculations be=3D
used?<br /><br = />Thanks</div></div></blockquote><span>&nbs= p;</span><br />T=3D
here is a bit of a culture and language issue here. We are taught all = sorts=3D
of models of bonding and electron behavior in our chemical = education, and =3D
it is sometimes dificult to realise that an electronic structure model, = as =3D
implemented by an ab initio program such as the one you mentioned, is a = dee=3D
per model where the language of interation which we inherit from the = simple=3D
r descriptions, may no longer be the most acurate way of describing what = is=3D
happening. By all means try open shell calculations, but be = prepared for t=3D
he eventuality that they may not clarify the picture in terms of a = simpler =3D
understanding.<br />All the best<br />Laurence Cuffe<br = /><br />=3DC2=3DA0<bloc=3D
kquote type=3D3D"cite"><div class=3D3D"msg-quote"><div = class=3D3D"_stretch"><br /=3D
><br /><br />-=3D3D This is automatically added to each = message by the mailin=3D
g script =3D3D-<br />To recover the email address of the author of = the messag=3D
e, please change<br />the strange characters on the top line to = the ]^[ sig=3D
n. You can also<br /<=3D
br /><br />E-mail to subscribers: <a href=3D3D"mailto:CHEMISTRY%5D%5E%5Bccl.n=3D=
et">CHEMISTRY]^[ccl.net</a> or use:<br /><a = href=3D3D"http://www.ccl.net/cgi-=3D
bin/ccl/send_ccl_message">http://www.ccl.net/cgi-bin/ccl/send_ccl_message</= =3D
a><br /><br />E-mail to administrators: <a = href=3D3D"mailto:CHEMISTRY-REQUEST=3D
%5D%5E%5Bccl.net">CHEMISTRY-REQUEST]^[ccl.net</a> or = use<br /><a href=3D3D"ht=3D
tp://www.ccl.net/cgi-bin/ccl/send_ccl_message">http://www.ccl.net/cgi-bin/c=3D
cl/send_ccl_message</a><br /><br = />Subscribe/Unsubscribe:<br /><a href=3D3D"h=3D
ttp://www.ccl.net/chemistry/sub_unsub.shtml">http://www.ccl.net/chemistry/s=3D
ub_unsub.shtml</a><br /><br />Before posting, = check wait time at: <a href=3D
=3D3D"http://www.ccl.net">http://www.ccl.net</a><br /><br = />Job: <a href=3D3D"h=3D
ttp://www.ccl.net/jobs">http://www.ccl.net/jobs</a><br = />Conferences: <a hr=3D
ef=3D3D"http://server.ccl.net/chemistry/announcements/conference= s/">http://se=3D
rver.ccl.net/chemistry/announcements/conferences/<= ;/a><br /><br />Search Mes=3D
sages: <a href=3D3D"http://www.ccl.net/chemistry/searchccl/index.shtml"&= gt;http:=3D
//www.ccl.net/chemistry/searchccl/index.shtml</a>= ;<br /><br /><a href=3D3D"htt=3D
p://www.ccl.net/spammers.txt">http://www.ccl.net/spammers.txt</a><br = /><br =3D
/>RTFI: <a href=3D3D"http://www.ccl.net/chemistry/aboutccl/instructions/"= >htt=3D
p://www.ccl.net/chemistry/aboutccl/instructions/</a&g= t;<br /><br />=3DC2=3DA0</div=3D
= ></div></blockquote></div></div></div><= ;/blockquote><p style=3D3D"margin:0px; =3D
padding:0px;" >=3DC2=3DA0</p></span></span>