From owner-chemistry@ccl.net Thu May 21 02:49:00 2009
From: "Marcel Swart marcel.swart]_[icrea.es" <owner-chemistry-,-server.ccl.net>
To: CCL
Subject: CCL: gas-phase acidity
Message-Id: <-39349-090521024732-29823-1b0gFmq+9LKAduNV6os+8g-,-server.ccl.net>
X-Original-From: Marcel Swart <marcel.swart*icrea.es>
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Date: Thu, 21 May 2009 08:42:59 +0200
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Sent to CCL by: Marcel Swart [marcel.swart,,icrea.es]
Hello Marian,
see our series of papers and references therein:
M. Swart and F.M. Bickelhaupt
"Proton Affinities of Anionic Bases: Trends Across the Periodic Table, =20
Structural Effects, and DFT Validation"
J. Chem. Theor. Comp. 2006, 2, 281-287
M. Swart, E. R=F6sler and F.M. Bickelhaupt
"Proton Affinities of Maingroup-Element Hydrides and Noble Gases: =20
Trends Across the Periodic Table, Structural Effects and DFT Validation"
J. Comput. Chem. 2006, 27, 1486-1493
M. Swart, E. R=F6sler and F.M. Bickelhaupt
"Proton Affinities in Water of Maingroup-Element Hydrides. Effects of =20
Hydration and Methyl Substitution"
Eur. J. Inorg. Chem. 2007, 3646-3654
and also:
Hunter, E. P. L.; Lias, S. G. J. Phys. Chem. Ref. Data 1998, 27, 413
Hope this helps.
Quoting "Marian Olaru om2006]![chem.ubbcluj.ro" <owner-chemistry{}ccl.net>:
>
> Sent to CCL by: "Marian Olaru" [om2006#chem.ubbcluj.ro]
> Hi there,
>
> I am a 2nd year student and recently I was given a task: to =20
> calculate the gas phase acidity for different protons of a molecule =20
> (more exactly I want to see which proton leaves from the molecule =20
> more easily). In order to do that I optimized the molecule and I did =20
> a frequencies calculation using Gammes software. The problem is =20
> that from the literature I read so far on the subject I do not =20
> understand exactly how I can calculate the gas phase acidity. =20
> Please give me some detailed information about the equations and =20
> principles used to calculate this gas phase acidity, and/or some =20
> books or articles suggestions for studying.
>
> Thank you.
>
>
>
> -=3D This is automatically added to each message by the mailing script =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=3D
dr. Marcel Swart
ICREA researcher at
Institut de Qu=EDmica Computacional
Universitat de Girona
Parc Cient=EDfic i Tecnol=F2gic
Edifici Jaume Casademont (despatx A-27)
Pic de Peguera 15
17003 Girona
Catalunya (Spain)
tel
+34-972-183240
fax
+34-972-183241
e-mail
marcel.swart{}icrea.es
marcel.swart{}udg.edu
web
http://www.icrea.cat/Web/ScientificForm.aspx?key=3D372
http://iqc.udg.edu/~marcel
=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
From owner-chemistry@ccl.net Thu May 21 11:27:00 2009
From: "Alfredo Tlahuice tlahuicef],[verizonmail.com" <owner-chemistry- -server.ccl.net>
To: CCL
Subject: CCL: Question about Buckyball and Ti
Message-Id: <-39350-090521111613-14989-QD1Yd4yUu67JmcAp0LkI7A- -server.ccl.net>
X-Original-From: "Alfredo Tlahuice" <tlahuicef:verizonmail.com>
Date: Thu, 21 May 2009 11:16:10 -0400
Sent to CCL by: "Alfredo Tlahuice" [tlahuicef^^verizonmail.com]
Hi there.
I'm trying to optimize a buckyball attached to a titanium atom and 2 H atoms.
I use the next keywords:
%chk=C60TiH2
%Mem=120MW
%nproc=12
# B3LYP/6-31G(d) SCF(IntRep,NoVarAcc,Tight) symm(loose,follow) freq=Raman
The questions is about I was not able to see a optimization step and It seems to me that the frequencies calculations is beeing done.
I'm sending you part of the output file.
Range of M.O.s used for correlation: 1 940
NBasis= 940 NAE= 192 NBE= 192 NFC= 0 NFV= 0
NROrb= 940 NOA= 192 NOB= 192 NVA= 748 NVB= 748
**** Warning!!: The smallest alpha delta epsilon is 0.68926344D-01
PrsmSu: requested number of processors reduced to: 1 ShMem 1 Linda.
Symmetrizing basis deriv contribution to polar:
IMax=3 JMax=2 DiffMx= 0.00D+00
G2DrvN: will do 3 centers at a time, making 22 passes doing MaxLOS=3.
FoFDir/FoFCou used for L=0 through L=3.
DoAtom=TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
DoAtom=TTTTTTTTTTTTT
Differentiating once with respect to electric field.
with respect to dipole field.
Differentiating once with respect to nuclear coordinates.
Integrals replicated using symmetry in FoFDir.
MinBra= 0 MaxBra= 3 Meth= 1.
IRaf= 0 NMat= 12 IRICut= 12 DoRegI=T DoRafI=T ISym2E= 2 JSym2E=2.
Raff turned off since only 57.72% of shell-pairs survive.
There are 60 degrees of freedom in the 1st order CPHF.
60 vectors were produced by pass 0.
AX will form 12 AO Fock derivatives at one time.
60 vectors were produced by pass 1.
60 vectors were produced by pass 2.
60 vectors were produced by pass 3.
Do you think the calculations is correct?
I think would be better if I use a 6-31g(d) basis for the C and H atoms and a LAND2DZ for the titanium atom, What do u think?
Any advices would be great.
From owner-chemistry@ccl.net Thu May 21 12:18:01 2009
From: "Rajagopalan S. r.subramanian_+_ipc.uni-stuttgart.de" <owner-chemistry++server.ccl.net>
To: CCL
Subject: CCL: Question about Buckyball and Ti
Message-Id: <-39351-090521121311-8198-5uyWPV54/ggZpcqh5V1YNA++server.ccl.net>
X-Original-From: "Rajagopalan S." <r.subramanian_._ipc.uni-stuttgart.de>
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Date: Thu, 21 May 2009 18:12:45 +0200
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Sent to CCL by: "Rajagopalan S." [r.subramanian-*-ipc.uni-stuttgart.de]
Hi,
replace 'freq=raman' keyword by 'opt'
Alfredo Tlahuice tlahuicef],[verizonmail.com wrote:
> Sent to CCL by: "Alfredo Tlahuice" [tlahuicef^^verizonmail.com]
> Hi there.
> I'm trying to optimize a buckyball attached to a titanium atom and 2 H atoms.
> I use the next keywords:
>
> %chk=C60TiH2
> %Mem=120MW
> %nproc=12
> # B3LYP/6-31G(d) SCF(IntRep,NoVarAcc,Tight) symm(loose,follow) freq=Raman
>
> The questions is about I was not able to see a optimization step and It seems to me that the frequencies calculations is beeing done.
>
> I'm sending you part of the output file.
> Range of M.O.s used for correlation: 1 940
> NBasis= 940 NAE= 192 NBE= 192 NFC= 0 NFV= 0
> NROrb= 940 NOA= 192 NOB= 192 NVA= 748 NVB= 748
>
> **** Warning!!: The smallest alpha delta epsilon is 0.68926344D-01
>
> PrsmSu: requested number of processors reduced to: 1 ShMem 1 Linda.
> Symmetrizing basis deriv contribution to polar:
> IMax=3 JMax=2 DiffMx= 0.00D+00
> G2DrvN: will do 3 centers at a time, making 22 passes doing MaxLOS=3.
> FoFDir/FoFCou used for L=0 through L=3.
> DoAtom=TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
> DoAtom=TTTTTTTTTTTTT
> Differentiating once with respect to electric field.
> with respect to dipole field.
> Differentiating once with respect to nuclear coordinates.
> Integrals replicated using symmetry in FoFDir.
> MinBra= 0 MaxBra= 3 Meth= 1.
> IRaf= 0 NMat= 12 IRICut= 12 DoRegI=T DoRafI=T ISym2E= 2 JSym2E=2.
> Raff turned off since only 57.72% of shell-pairs survive.
> There are 60 degrees of freedom in the 1st order CPHF.
> 60 vectors were produced by pass 0.
> AX will form 12 AO Fock derivatives at one time.
> 60 vectors were produced by pass 1.
> 60 vectors were produced by pass 2.
> 60 vectors were produced by pass 3.
>
> Do you think the calculations is correct?
> I think would be better if I use a 6-31g(d) basis for the C and H atoms and a LAND2DZ for the titanium atom, What do u think?
>
> Any advices would be great.>
>
>
From owner-chemistry@ccl.net Thu May 21 16:44:00 2009
From: "Ramachandran Chelat rcchelat:-:rediffmail.com" <owner-chemistry\a/server.ccl.net>
To: CCL
Subject: CCL:G: default convergence criteria in Gamess and Gaussian
Message-Id: <-39352-090521123232-20288-aCQadkONJS2fL5/GTyU6jQ\a/server.ccl.net>
X-Original-From: "Ramachandran Chelat" <rcchelat . rediffmail.com>
Date: Thu, 21 May 2009 12:32:28 -0400
Sent to CCL by: "Ramachandran Chelat" [rcchelat%rediffmail.com]
Dear CCL friends,
Let me know about the default convergence criteria in GAMESS and GAUSSIAN
I did some optimization using Gamess using the default values and did a frequency calculation using default parameters.
As my systems have shallow potential energy surfaces I expect several maxima and minima. However for some cases, I got only imaginary frequencies.
By identifying the frequencies, I changed the structure slightly and did the optimization and frequency calculation again. It also end up with the imaginary frequencies.
I got some suggestions to increase the gradient convergence tolerance OPTTOL to 10^-7 or 10^-8 (The default is 10^-4 in GAMESS).
I would like to know how the default values of GAMESS and GAUSSIAN differ?
My intention is to locate the maximum number of minima and maxima of the structures.
Thanking you,
Ramachandran