From owner-chemistry@ccl.net Sat May 10 11:12:01 2008 From: "Ali S alsa38]=[gmail.com" To: CCL Subject: CCL: Maximum Force Message-Id: <-36930-080510042541-12520-nXymrcMd2arbYfUROlizRg++server.ccl.net> X-Original-From: "Ali S" Date: Sat, 10 May 2008 04:25:36 -0400 Sent to CCL by: "Ali S" [alsa38 ~~ gmail.com] Dear CCL Subscribers I have a problem in the optimization. I want to optimize two monomer ( inorganic-organic compound with 50 atoms of C, H, N, Cl and Sn) that these intreact with each other by strong hydrogen bonding. These monomers have the same structure. In the process of optimization (RHF/6-31G) the value of Maximum force is up (>9.9999 that appears ********). Can you help me about this? Thanks a lot for your attention. From owner-chemistry@ccl.net Sat May 10 14:53:01 2008 From: "D. Boyd boyd^^^chem.iupui.edu" To: CCL Subject: CCL: Undergraduate research question Message-Id: <-36931-080509230441-31768-wbIfHPeLgoddGzQlubMNvQ^server.ccl.net> X-Original-From: "D. Boyd" Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; format=flowed Date: Fri, 9 May 2008 22:04:24 -0400 Mime-Version: 1.0 (Apple Message framework v624) Sent to CCL by: "D. Boyd" [boyd],[chem.iupui.edu] Barbara, You have already received some good feedback in regard to your posting on CCl. Quantum chemistry and molecular simulations tend to be taught and used in college. If your talented student wants to be a pharmaceutical chemist, he would do well to use his undergraduate research experience to learn QSAR. This plays a larger role in pharmaceutical research. Database mining and cheminformatics are also important. You already have Spartan. It can be used to generate molecular properties for QSAR analysis. There are also tools available on the Internet; see past CCL postings. The most important methodologies for "real" pharmaceutical chemists have been discussed in various places, e.g., D. B. Boyd and K. B. Lipkowitz, Examination of the Employment Environment for Computational Chemistry. In Reviews in Computational Chemistry, K. B. Lipkowitz and D. B. Boyd, Eds., Wiley-VCH, Hoboken, NJ, 2002, Vol. 18, pp. 293-319. D. B. Boyd, How Computational Chemistry Became Important in the Pharmaceutical Industry. In Reviews in Computational Chemistry, K. B. Lipkowitz and T. Cundari, Eds., Wiley-VCH, Hoboken, NJ, 2007, Vol. 23, pp. 401-451. Don Donald B. Boyd, Ph.D. Department of Chemistry and Chemical Biology Indiana University-Purdue University at Indianapolis From owner-chemistry@ccl.net Sat May 10 15:31:01 2008 From: "Radhakrishnan Sarangapani radhas78%a%gmail.com" To: CCL Subject: CCL:G: Solute radius for the SCRF calculation Message-Id: <-36932-080510024634-6378-jCux5H6rS3DYjOEmICXDlQ]^[server.ccl.net> X-Original-From: "Radhakrishnan Sarangapani" Content-Type: multipart/alternative; boundary="----=_Part_7287_8389121.1210400236422" Date: Sat, 10 May 2008 11:47:16 +0530 MIME-Version: 1.0 Sent to CCL by: "Radhakrishnan Sarangapani" [radhas78(a)gmail.com] ------=_Part_7287_8389121.1210400236422 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Hi, Since Monte-Carlo integration is performed, the computed volume is only accurate to about two significant figures, but this is sufficient to estimate a radius for use with the Onsager solvent reaction field model: this is what written in Gaussian Manual. You can add volume=tight option and you can restart the calculation with same method from its chk file again and again. This may near to the constant value. Other alternative is Materials Studio software's packing calculations.... with regards, Radhakrishnan On 5/9/08, Rishi Pandey rish.iisc*|*gmail.com wrote: > > > Sent to CCL by: "Rishi Pandey" [rish.iisc||gmail.com] > Dear all, > I want to perform some SFRF calculations using Onsager model(Gaussian 03 > program).Calculation requires the solute radius in the gas phase which can > be calculated using Volume keyword.I run a Volume job thrice starting from > the identical input as well as the job setup(basis set-b3lyp-6311g**).I got > three diffrent solute radai.I wonder how can I find out which one is the > right one. > > I will heartly appreciate for anykind of suggestions. > > Regards > Rishi> > > -- Dr S Radhakrishnan Scientist, CEPP Division, High Energy Materials Research Laboratory, Pune, Maharashtra, India ------=_Part_7287_8389121.1210400236422 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline
Hi,
Since Monte-Carlo integration is performed, the computed volume is only accurate to about two significant figures, but this is sufficient to estimate a radius for use with the Onsager solvent reaction field model:  this is what written in Gaussian Manual.
You can add volume=tight option and you can restart the calculation with same method from its chk file again and again.  This may near to the constant value.
Other alternative is Materials Studio software's packing calculations....
 
with regards,
 
Radhakrishnan
 
 

 
On 5/9/08, Rishi Pandey rish.iisc*|*gmail.com <owner-chemistry(a)ccl.net> wrote:

Sent to CCL by: "Rishi  Pandey" [rish.iisc||gmail.com]
Dear all,
I want to perform some SFRF calculations using Onsager model(Gaussian 03 program).Calculation requires the solute radius in the gas phase which can be calculated using Volume keyword.I run a Volume job thrice starting from the identical input as well as the job setup(basis set-b3lyp-6311g**).I got three diffrent solute radai.I wonder how can I find out which one is the right one.

I will heartly appreciate for anykind of suggestions.

Regards
Rishi



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--
Dr S Radhakrishnan
Scientist, CEPP Division,
High Energy Materials Research Laboratory,
Pune, Maharashtra, India ------=_Part_7287_8389121.1210400236422--