From owner-chemistry@ccl.net Mon Feb 15 09:00:00 2010 From: "Mariusz Radon mariusz.radon-*-gmail.com" To: CCL Subject: CCL: BSSE MP2 Basis set Message-Id: <-41252-100215084843-5467-eIHOxR2X4oPLGLCCW9UTNw%server.ccl.net> X-Original-From: Mariusz Radon Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Mon, 15 Feb 2010 14:41:20 +0100 MIME-Version: 1.0 Sent to CCL by: Mariusz Radon [mariusz.radon::gmail.com] Dear Roy, Such large BSSE are known and rather typical in correlated ab initio calculations (like MP2, CASPT2) with "small" basis. Compare, e.g., Table 5 in this paper [doi: 10.1016/j.chemphys.2006.11.036]. Thus I wouldn't say that large BSSE makes you calculations untrustable. However, large BSSE clearly evidences that your basis set is small (and possibly too small). You will never know this before you try the larger basis. > Also, such complex dimer, I not sure which > basis set isl better, 6-31+G(d) or 6311+G(d). 6-311+G(d) [valence-polarized triple-zeta + diffuse] is a more extensive basis than 6-31+G(d) [valence-polarized double-zeta + diffuse], thus most probably the "better" one. Have you tried Dunning correlation consistent basis sets instead of Pople's basis sets? They are better suited for correlated methods and have more systematic improvement with respect to increase of the basis set. I would try cc-pVDZ, aug-cc-pVDZ, and cc-pVTZ (maybe aug-cc-pVTZ if you can), and compare the results. This will give you some idea on how much your results are sensitive to the basis set. Comparison withing the first pair (aug-cc-pVDZ vs cc-pVDZ) would give you an estimate how much the diffuse functions (aug-) are important. The second pair (cc-pVTZ vs cc-pVDZ) would give you an estimate how much your results depend on n in cc-pVnZ family (n=3D2,3,...). Hope it will be helpful. Best regards, Mariusz Radon On Sun, Feb 14, 2010 at 8:37 PM, Roy Green powergreen*gmail.com wrote: > > Dear All, > > Can I believe the BSSE corrections if the the BSSE was comparable to the = MP2 > bonding energies before BSSE correction? I used a multi-reference based M= P2 > method for a complex pi-dimer. Also, such complex dimer, I not sure which > basis set isl better, 6-31+G(d) or 6311+G(d). Due to the computational > limitation, I can not use larger=C2=A0 basis set. > Thanks. > > Roy > > --=20 Mariusz Radon, PhD student Department of Theoretical Chemistry Jagiellonian University http://www.chemia.uj.edu.pl/~mradon mradon /at/ chemia.uj.edu.pl (PGP public key available on the website) From owner-chemistry@ccl.net Mon Feb 15 10:31:00 2010 From: "Pierre Archirel pierre.archirel||u-psud.fr" To: CCL Subject: CCL:G: gaussian 09: difficulties with IRC Message-Id: <-41253-100215102201-13865-duMIk8V+4xYqEwBYy4cXyA:-:server.ccl.net> X-Original-From: "Pierre Archirel" Date: Mon, 15 Feb 2010 10:21:58 -0500 Sent to CCL by: "Pierre Archirel" [pierre.archirel^u-psud.fr] Dear colleagues, I have localised a TS for a probably floppy molecule (a seven membered ring), I now wish to follow down the reaction path to the potential wells. The question is that gaussian 09 simply cannot depart, probably because the barrier top is too flat. How can I fix this issue? Thanks in advance. These is my data line: irc=(forward,calcfc,hpc,maxpoints=200,maxcycle=50,stepsize=10,tight) I have varied two options: stepsize=10, 20 and 50 and ordinary, tight and vtight accuracy, and combinations of them. This is a typical output: IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC Error in corrector energy = 0.0000000087 Magnitude of corrector gradient = 0.0000440598 Magnitude of analytic gradient = 0.0000465467 Magnitude of difference = 0.0000332442 Angle between gradients (degrees)= 42.9405 Pt 1 Step number 20 out of a maximum of 50 CORRECTOR INTEGRATION CONVERGENCE: Recorrection delta-x convergence threshold: 0.001826 Delta-x Convergence Met Point Number: 1 Path Number: 1 CHANGE IN THE REACTION COORDINATE = 0.00327 NET REACTION COORDINATE UP TO THIS POINT = 0.00327 # OF POINTS ALONG THE PATH = 1 # OF STEPS = 20 PES minimum detected on this side of the pathway. Magnitude of the gradient = 0.0000441 Calculation of FORWARD path complete. Reaction path calculation complete. Energies reported relative to the TS energy of -204.117456 -------------------------------------------------------------------------- Summary of reaction path following -------------------------------------------------------------------------- Energy Rx Coord 1 0.00000 0.00000 2 0.00000 0.00327 -------------------------------------------------------------------------- Total number of points: 1 Total number of gradient calculations: 21 Total number of Hessian calculations: 1 IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC-IRC Pierre Archirel pierre.archirel|u-psud.fr From owner-chemistry@ccl.net Mon Feb 15 13:19:01 2010 From: "Roy Green powergreen|,|gmail.com" To: CCL Subject: CCL: BSSE MP2 Basis set Message-Id: <-41254-100215131741-12016-DqdveY7D7AWtyZekbSnvtA|,|server.ccl.net> X-Original-From: Roy Green Content-Type: multipart/alternative; boundary=00c09f8de8b230ffa9047fa7a19b Date: Mon, 15 Feb 2010 13:17:27 -0500 MIME-Version: 1.0 Sent to CCL by: Roy Green [powergreen:-:gmail.com] --00c09f8de8b230ffa9047fa7a19b Content-Type: text/plain; charset=ISO-8859-1 Dear Mariusz, Thank you for your message. It is very helpful. Best, Roy On Mon, Feb 15, 2010 at 8:41 AM, Mariusz Radon mariusz.radon-*-gmail.com < owner-chemistry*|*ccl.net> wrote: > > Sent to CCL by: Mariusz Radon [mariusz.radon::gmail.com] > Dear Roy, > > Such large BSSE are known and rather typical in correlated ab initio > calculations (like MP2, CASPT2) with "small" basis. Compare, e.g., > Table 5 in this paper > [doi: 10.1016/j.chemphys.2006.11.036]. > Thus I wouldn't say that large BSSE makes you calculations > untrustable. However, large BSSE clearly evidences that your basis set > is small (and possibly too small). You will never know this before you > try the larger basis. > > > Also, such complex dimer, I not sure which > > basis set isl better, 6-31+G(d) or 6311+G(d). > > 6-311+G(d) [valence-polarized triple-zeta + diffuse] is a more > extensive basis than 6-31+G(d) [valence-polarized double-zeta + > diffuse], thus most probably the "better" one. > > Have you tried Dunning correlation consistent basis sets instead of > Pople's basis sets? They are better suited for correlated methods and > have more systematic improvement with respect to increase of the basis > set. I would try cc-pVDZ, aug-cc-pVDZ, and cc-pVTZ (maybe aug-cc-pVTZ > if you can), and compare the results. This will give you some idea on > how much your results are sensitive to the basis set. Comparison > withing the first pair (aug-cc-pVDZ vs cc-pVDZ) would give you an > estimate how much the diffuse functions (aug-) are important. The > second pair (cc-pVTZ vs cc-pVDZ) would give you an estimate how much > your results depend on n in cc-pVnZ family (n=2,3,...). > > Hope it will be helpful. > > Best regards, > Mariusz Radon > > > On Sun, Feb 14, 2010 at 8:37 PM, Roy Green powergreen*gmail.com > wrote: > > > > Dear All, > > > > Can I believe the BSSE corrections if the the BSSE was comparable to the > MP2 > > bonding energies before BSSE correction? I used a multi-reference based > MP2 > > method for a complex pi-dimer. Also, such complex dimer, I not sure which > > basis set isl better, 6-31+G(d) or 6311+G(d). Due to the computational > > limitation, I can not use larger basis set. > > Thanks. > > > > Roy > > > > > > > > -- > Mariusz Radon, PhD student > Department of Theoretical Chemistry > Jagiellonian University > http://www.chemia.uj.edu.pl/~mradon > mradon /at/ chemia.uj.edu.pl > (PGP public key available on the website) > > > > - This is automatically added to each message by the mailing script -> > > --00c09f8de8b230ffa9047fa7a19b Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Dear Mariusz,

Thank you for your message. It is very helpful.
Best,

Roy

On Mon, Feb 15, 2010 at= 8:41 AM, Mariusz Radon mariusz.radon-*-gmail.= com <ow= ner-chemistry*|*ccl.net> wrote:

Sent to CCL by: Mariusz Radon [mariusz.radon::gmail.com]
Dear Roy,

Such large BSSE are known and rather typical in correlated ab initio
calculations (like MP2, CASPT2) with "small" basis. Compare, e.g.= ,
Table 5 in this paper
[doi: 10.1016/j.chemphys.2006.11.036].
Thus I wouldn't say that large BSSE makes you calculations
untrustable. However, large BSSE clearly evidences that your basis set
is small (and possibly too small). You will never know this before you
try the larger basis.

> Also, such complex dimer, I not sure which
> basis set isl better, 6-31+G(d) or 6311+G(d).

6-311+G(d) [valence-polarized triple-zeta + diffuse] is a more
extensive basis than 6-31+G(d) [valence-polarized double-zeta +
diffuse], thus most probably the "better" one.

Have you tried Dunning correlation consistent basis sets instead of
Pople's =A0basis sets? They are better suited for correlated methods an= d
have more systematic improvement with respect to increase of the basis
set. I would try cc-pVDZ, aug-cc-pVDZ, and cc-pVTZ (maybe aug-cc-pVTZ
if you can), and compare the results. This will give you some idea on
how much your results are sensitive to the basis set. Comparison
withing the first pair (aug-cc-pVDZ vs cc-pVDZ) would give you an
estimate how much the diffuse functions (aug-) are important. The
second pair (cc-pVTZ vs cc-pVDZ) would give you an estimate how much
your results depend on n in cc-pVnZ family (n=3D2,3,...).

Hope it will be helpful.

Best regards,
Mariusz Radon


On Sun, Feb 14, 2010 at 8:37 PM, Roy Green powergreen*gmail.com
<owner-chemistry ~ ccl.net<= /a>> wrote:
>
> Dear All,
>
> Can I believe the BSSE corrections if the the BSSE was comparable to t= he MP2
> bonding energies before BSSE correction? I used a multi-reference base= d MP2
> method for a complex pi-dimer. Also, such complex dimer, I not sure wh= ich
> basis set isl better, 6-31+G(d) or 6311+G(d). Due to the computational=
> limitation, I can not use larger=A0 basis set.
> Thanks.
>
> Roy
>
>



--
Mariusz Radon, PhD student
Department of Theoretical Chemistry
Jagiellonian University
http://= www.chemia.uj.edu.pl/~mradon
mradon /at/ chemia.uj= .edu.pl
(PGP public key available on the website)



- This is automatically added to each message by the mailing script -
E-mail to subscribers: CHEMISTRY*|*ccl.n= et or use:
=A0 =A0 =A0http://www.ccl.net/cgi-bin/ccl/send_ccl_message

E-mail to administrators: CHEM= ISTRY-REQUEST*|*ccl.net or use
=A0 =A0 =A0http://www.ccl.net/cgi-bin/ccl/send_ccl_message

Subscribe/Unsubscribe:
=A0 =A0 =A0http://www.ccl.net/chemistry/sub_unsub.shtml

Before posting, check wait time at: http://www.ccl.net

Job: http://www.ccl.n= et/jobs
Conferences: http://server.ccl.net/chemistry/announcements/co= nferences/

Search Messages: http://www.ccl.net/chemistry/searchccl/index.shtml
=A0 =A0 =A0h= ttp://www.ccl.net/spammers.txt

RTFI: http://www.ccl.net/chemistry/aboutccl/instructions/



--00c09f8de8b230ffa9047fa7a19b-- From owner-chemistry@ccl.net Mon Feb 15 13:54:01 2010 From: "Dhurairajan Senthilnathan zenthil03(~)yahoo.co.in" To: CCL Subject: CCL:G: TDDFT calculations Message-Id: <-41255-100215135233-28562-mM9BWj56CIJMr3me6G8X1A_+_server.ccl.net> X-Original-From: "Dhurairajan Senthilnathan" Date: Mon, 15 Feb 2010 13:52:29 -0500 Sent to CCL by: "Dhurairajan Senthilnathan" [zenthil03(~)yahoo.co.in] Dear CCLrs, Greetings, any one of you please give the answers for the following doubts. This is regarding TDDFT calculations. I got some results in this calculation using Gaussian03. My questions are 1. What is the significance of Oscillator strengths ( f )? 2. How can we correlate the TDDFT results with complex stability? 3. How one can draw the theoretical UV spectrum by the output values? Your answers will be more valuable to me Yours Sincerely Dhurairajan Senthilnathan From owner-chemistry@ccl.net Mon Feb 15 14:58:01 2010 From: "=?ISO-8859-1?Q?Ulf_Ekstr=F6m?= ulfek,+,few.vu.nl" To: CCL Subject: CCL: TDDFT calculations Message-Id: <-41256-100215145609-8692-mfsPZe4eJ7ug6tGqeFLgDQ++server.ccl.net> X-Original-From: =?ISO-8859-1?Q?Ulf_Ekstr=F6m?= Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=ISO-8859-1 Date: Mon, 15 Feb 2010 20:55:56 +0100 MIME-Version: 1.0 Sent to CCL by: =?ISO-8859-1?Q?Ulf_Ekstr=F6m?= [ulfek[]few.vu.nl] On Mon, Feb 15, 2010 at 7:52 PM, Dhurairajan Senthilnathan zenthil03(~)yahoo.co.in wrote: > > Sent to CCL by: "Dhurairajan =A0Senthilnathan" [zenthil03(~)yahoo.co.in] [..] > My questions are > > 1. =A0 =A0 =A0What is the significance of Oscillator strengths ( f )? I think it would be easier for us to help you if you explained what it is you don't understand about the usual textbook explanation. The Wikipedia page on oscillator strengths (the first link you surely found with google) even has a useful and friendly reference. Sincerely, Ulf Ekstr=F6m, VU University Amsterdam From owner-chemistry@ccl.net Mon Feb 15 17:08:00 2010 From: "l l leonids26(0)gmail.com" To: CCL Subject: CCL:G: TDDFT calculations Message-Id: <-41257-100215170436-15013-OTHfpc18JIMSvql3MpGjaw()server.ccl.net> X-Original-From: l l Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=ISO-8859-1 Date: Tue, 16 Feb 2010 01:04:23 +0300 MIME-Version: 1.0 Sent to CCL by: l l [leonids26*gmail.com] > 3. How one can draw the theoretical UV spectrum by the output values? You can use Chemissian program (www.chemissian.com) to automatically plot TDDFT (and CIS) UV-VIS spectra from the Gamess, Firefly(PC-Gamess) and Gaussian output files. Different useful options are available: several spectra on a single diagram, displaying transitions directly on the MO diagram, adding (one or more) experimental spectrum data, Gaussian/Lorentzian line-shapes, adding text labels, etc. See examples here: http://www.chemissian.com/assignmentofpeaks http://www.chemissian.com/ch180 2010/2/15 Dhurairajan Senthilnathan zenthil03(~)yahoo.co.in : > > Sent to CCL by: "Dhurairajan =A0Senthilnathan" [zenthil03(~)yahoo.co.in] > Dear CCLrs, > > =A0 =A0 =A0 =A0Greetings, any one of you please give the answers for the = following doubts. > > This is regarding TDDFT calculations. I got some results in this calculat= ion using Gaussian03. > > My questions are > > 1. =A0 =A0 =A0What is the significance of Oscillator strengths ( f )? > 2. =A0 =A0 =A0How can we correlate the TDDFT results with complex stabili= ty? > 3. =A0 =A0 =A0How one can draw the theoretical UV spectrum by the output = values? > > Your answers will be more valuable to me > > Yours Sincerely > > Dhurairajan Senthilnathan > > > > -=3D This is automatically added to each message by the mailing script = =3D-> =A0 =A0 =A0http://www.ccl.net/cgi-bin/ccl/send_ccl_message> =A0 =A0 =A0http://www.ccl.net/cgi-bin/ccl/send_ccl_message> =A0 =A0 =A0http://www.ccl.net/chemistry/sub_unsub.shtml> =A0 =A0 =A0http://www.ccl.net/spammers.txt> > >