From owner-chemistry@ccl.net Sun May 29 07:48:00 2011 From: "=?ISO-8859-1?Q?=D6d=F6n?= Farkas farkas _ chem.elte.hu" To: CCL Subject: CCL: Doubt on Optmization Output Message-Id: <-44784-110529072233-6990-E9O266xzYOANkHnwB4ppQg.:.server.ccl.net> X-Original-From: =?ISO-8859-1?Q?=D6d=F6n?= Farkas Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="UTF-8" Date: Sun, 29 May 2011 13:20:59 +0200 Mime-Version: 1.0 Sent to CCL by: =?ISO-8859-1?Q?=D6d=F6n?= Farkas [farkas : chem.elte.hu] Hi Guilherme, If you are not sure just continue the optimization with Opt=Tight or even Opt=verytight. I usually use Opt=(Tight, GDIIS) which helps on flat potentials. Good luck, Ödön -- Ödön Farkas Associate professor Deparment of Organic Chemistry and Laboratory of Chemical Informatics, Institute of Chemistry, Eötvös Loránd University, Budapest Address: 1/A Pázmány Péter sétány, H-1117 Budapest, Hungary Phone: +36-1-372-2570 Cell phone: +36-30-255-3111 Fax: +36-1-372-2620 URL: http://organ.elte.hu/farkas From owner-chemistry@ccl.net Sun May 29 11:09:01 2011 From: "Andreas Klamt klamt-*-cosmologic.de" To: CCL Subject: CCL:G: Solvation free energies Message-Id: <-44785-110529040553-1907-mvqMLjMh3OyXTz5eojmBRg,,server.ccl.net> X-Original-From: Andreas Klamt Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=ISO-8859-15; format=flowed Date: Sun, 29 May 2011 10:05:45 +0200 MIME-Version: 1.0 Sent to CCL by: Andreas Klamt [klamt^^cosmologic.de] Hi John, hi Pierre, I am owing you answers on your last entries on this topic. Sorry for not having been able to respond more timely. John: First own the strange values reported by John: I did your molecule (just single point) with COSMOtherm, and my results are: - dG_solv in hexane (1bar vs. 1mol/mol) of -31 kcal/mol (or ca. -34 kcal/mol mit referenz is molar in gas phase and solution) We have ca. -3.5 kcal/mol electrostatic and ca. -28 kcal/mol non-electrostatic contribution to the free energy. Something must be dramatically wrong with your Gaussian results.I do not know whether you made any mistake or whether it is a bug in the program. Pierre: I cannot follow your arguments on the entropy of water in water. In the liquid phase a large part of the entropy comes from the number of arrangements of the molecule with respect to its neighbors. Within the COSMO-RS theory this is the entropy of the possible pairings of all surface segments (size bing the area of an effectively independent surface segment, which is ~7 Angstrom²). A crude calculation shows that in water due to the high polarity of the surface segments only pos-neg-pair can occur at room temperature. Since we have ~ 6 contact areas per molecule, this results in an entropy of 6*R*ln(0.5), while in an alkane of the same size all contacts can be made. How can you separate such contributions out of the overall entropy and speculate about the translational and rotational contribution? I do not see how this should be possible. Andreas Am 24.05.2011 16:50, schrieb Pierre Archirel pierre.archirel{}u-psud.fr: > Sent to CCL by: "Pierre Archirel" [pierre.archirel^^u-psud.fr] > Dear John, dear Andreas, > I recently stated that translation-rotation entropies in water amounts to roughly 30% of the values in the vacuum. I now explain this statement, though I have not the numbers under the hand: > 1- Str(vac, 1atm) is the translation-rotation entropy of H2O in the gas phase (Sackur-Tetrode + rigid rotor), you may remove -RLn 24.5 for having water gazeous and 1M. > 2- the experimental value of the standard molar entropy of liquid water is known: S^0 (for water 55.5M) > 3- if you add +RLn (55.5) to S^0 (for having water in solution 1M in itself) and remove the vibration entropy (calculated with harmonic analysis), then you get a number roughly 30% of the 1M gas phase value. > I conclude that passing from 1M gas phase to 1M solution (in itself), water molecules undergo a 70% decrease of their translation-rotation entropy. > > I acknowledge that I here assume that vibration can be separated from other motions, anyway the same reasoning is possible for the whole translation-rotation-vibration entropy. > > Pierre Archirel > LCP universite Paris-Sud > France > pierre.archirel|u-psud.fr> > > -- PD. Dr. Andreas Klamt CEO / Geschäftsführer COSMOlogic GmbH& Co. KG Burscheider Strasse 515 D-51381 Leverkusen, Germany phone +49-2171-731681 fax +49-2171-731689 e-mail klamt(0)cosmologic.de web www.cosmologic.de HRA 20653 Amtsgericht Koeln, GF: Dr. Andreas Klamt Komplementaer: COSMOlogic Verwaltungs GmbH HRB 49501 Amtsgericht Koeln, GF: Dr. Andreas Klamt From owner-chemistry@ccl.net Sun May 29 13:49:01 2011 From: "Juneyi Sung juneyi1#yahoo.com.tw" To: CCL Subject: CCL:G: Fractional total charge Message-Id: <-44786-110529134751-32702-eJ9s/Mp8/sWLLLm7VN7KNw]=[server.ccl.net> X-Original-From: "Juneyi Sung" Date: Sun, 29 May 2011 13:47:49 -0400 Sent to CCL by: "Juneyi Sung" [juneyi1(0)yahoo.com.tw] Dear CCLers, Is it correct that one can not input fractional total charge in Gaussian ? If so, what is the origin for that ? thanks Juneyi From owner-chemistry@ccl.net Sun May 29 16:33:00 2011 From: "ABHISHEK SHAHI shahi.abhishek1984]~[gmail.com" To: CCL Subject: CCL: why only emission ?? Message-Id: <-44787-110529162955-1937-rwbWIatBll1nH9WbQnS8bA+*+server.ccl.net> X-Original-From: ABHISHEK SHAHI Content-Type: multipart/alternative; boundary=0015175cfc4610cab204a4700813 Date: Mon, 30 May 2011 01:59:45 +0530 MIME-Version: 1.0 Sent to CCL by: ABHISHEK SHAHI [shahi.abhishek1984]|[gmail.com] --0015175cfc4610cab204a4700813 Content-Type: text/plain; charset=ISO-8859-1 Dear All, Instead of computational problem, here i have a conceptual problem. Why in NMR and microwave spectroscopy(rotational), we use only emission line to record the spectrum ? why absorption detection is difficult in MW/NMR ? Every suggestions are valuable for me.Thanks in advance. ######################################################## *Using Gmail? Please read this important notice: http://www.fsf.org/campaigns/jstrap/gmail?28230.* ######################################################## With regards; *ABHISHEK SHAHI* *Research Scholar Inorganic and Physical Chemistry Indian Institute Of Science Bangalore-12* E-mail: shahi!=!ipc.iisc.ernet.in shahi.abhishek1984!=!gmail.com * Contact No's :* *+91-80-2293-2384 (LAB) ** ** +91-9535 14 6005(MOB.)* ################################################# --0015175cfc4610cab204a4700813 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Dear All,

=A0=A0 Instead of computational problem, here i have a co= nceptual problem. Why in NMR and microwave spectroscopy(rotational), we use= only emission line to record the spectrum ? why absorption detection is di= fficult in MW/NMR ?

=A0 Every suggestions are valuable for me.Thanks in advance.

= =A0



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With regards;<= br>=A0ABHISHEK SHAHI

Research ScholarInorganic= and Physical Chemistry
In= dian Institute Of Science
Bangalore-12
E-mail: =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 shahi!=!ipc.iisc.ernet.in
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Contact No's := =A0=A0=A0=A0=A0=A0=A0=A0 +91-= 80-2293-2384 (LAB)
=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0= =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0= +91= -9535 14 6005(MOB.)
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