From chemistry-request@server.ccl.net Sun Aug 25 14:51:00 2002 Received: from moe.cs.uoguelph.ca ([131.104.96.55]) by server.ccl.net (8.11.6/8.11.0) with ESMTP id g7PIp0r26372 for ; Sun, 25 Aug 2002 14:51:00 -0400 Received: from smith ([131.104.32.146]) by moe.cs.uoguelph.ca (8.11.6/8.11.6) with ESMTP id g7PIovu06210; Sun, 25 Aug 2002 14:50:57 -0400 From: "W.R. Smith" To: knauerc , Michael J Zehe Date: Sun, 25 Aug 2002 14:48:53 -0400 MIME-Version: 1.0 Subject: Re: CCL:SUMMARY:Equilibrium Constants Reply-to: bilsmith@uoguelph.ca CC: chemistry@ccl.net Message-ID: <3D68EE55.30467.70448B@localhost> Priority: normal In-reply-to: <5.1.0.14.2.20020816133036.00a793b0@popserve.grc.nasa.gov> References: <3D52C65A.1728A54E@georgetown.edu> X-mailer: Pegasus Mail for Windows (v4.02) Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Content-description: Mail message body Hi, My $0.02 worth on the use of the Shomate (or any other) polynomial form to represent Cp values of gases: Polynomial fits to data do _not_ extrapolate well outside the range over which the data was fitted. This is usually only a problem with high-T gas phase data. For Cp values, I prefer to use the Aly-Lee form, which has good high-T extrapolation properties. This form is used in the database EQS4WIN software I mentioned earlier. http://www.mathtrek.com On 16 Aug 2002 at 13:49, Michael J Zehe wrote: > > Dear Everyone: > Many people have communicated to say that they can't hook up to the > NASA Glenn CEA site referenced below because the link was not working: > the link should have been without the final character, use : > http://www.grc.nasa.gov/www/ceaweb > > Others have commented about the convenience of the PFC program for > obtaining thermodynamic functions and have asked for details about its > input data. The CEA database consists of blocks of coefficients to the > following 'Shomate plus" equation: > > Cpo (T)/R = a1T-2 + a2T-1 + a3 + a4T + a5T2 + a6T3+ a7T4 > > plus integration constants for H and S. This form was chosen because > it allows accurate fits over a wide temperature range. Input data is > taken from standard compilations, from the literature, or calculated > from published spectroscopic data. The data are updated > almost continuously and documented thoroughly. > > CEA and its database are heavily used by the aerodynamics communiity > for rocket and jet engine design and analysis, and the database has > grown from 42 species in its first published version (in 1951) to the > current 2000. Much of this information is contained at > > http://www.grc.nasa.gov/www/ceaweb > > Also soon available will be a report NASA/TP-2002-211556, available > from Ms.McBride > at the above site. > > > > At 03:28 PM 08/08/2002 -0400, knauerc wrote: > Thanks to everyone for your help, and my apologies for being > so late in posting this summary of responses. > > My question was: > > Does anyone know where I can find good data for the equilibrium > constants, (as a function of temperature), for the reactions: > > H2 + Cl2 = 2HCl > > and > > H2 + Br2 = 2HBr > > The answers I received were: > > 1) Abhishek Jha (ajha@midway.uchicago.edu) > > Hi! > Try www.nist.gov > I have used this before so I am sure you will get what you are > looking for. Best of luck! > > Cheers! > Abhishek Jha > > > 2) Wayne Steinmetz (WES04747@pomona.edu) > > Consider using the JANF Thermochemical Tables. > > 3) Bill Smith (bilsmith@uoguelph.ca) > > Apart from standard tables like the JANAF Tables > (CHASE,M.,Jr.,1998, {\it NIST-JANAF Thermochemical Tables, 4th > ed., J. Phys. and Chem. Reference Data Monograph No. 9,} (Am. > Chem. Society, Am. Inst. Physics).Data, you can get a lot of this > data from the free Lite version of the reaction equilibrium > software package EQS4WIN, available at > > http://www.mathtrek.com > > 4) Chuck McFarland (cwm001@apk.net) > > Given that enthalpy and entropy easily lead to free energies, > which in turn lead to equilibrium constants, and that Shomate > equation coefficients give temperature dependence, most, if not > all, of what you need is at > > http://webbook.nist.gov/chemistry/ > > 5) David Shobe (dshobe@sud-chemieinc.com) > > The NIST WebBook (http://webbook.nist.gov/chemistry/) has > thermochemical data as a function of temperature, and you can > calculate equilibrium constants in the usual way. > > (Also note that the answers and necessary data sets will differ > considerably for gas-phase and aqueous-phase equilibrium > constants). > > 6) Viswanathan Balakrishnan (bviswan@chem1.chem.dal.ca) > > The equilibrium constants can be calculated from the thermodynamic > data available at http://webbook.nist.gov/chemistry/ > > 7) Michael J. Zehe (Michael.J.Zehe@grc.nasa.gov) > > A convenient source of up-to-date thermodynamic data in an > easily-used form is the program PFC, at http://cea.grc.nasa.gov/. > PFC allows the user to get accurate data for over 2000 species > contained in the NASA Glenn, (formerly NASA Lewis),database > documented in NASA TP-2002-211556 and at > http://www>.grc.nasa.gov/www/ceaweb>. This database has been > maintained and documented for almost 50 years by Ms. Bonnie > Mcbride et al at NASA Glenn in support of the NASA chemical > equilibrium program CEA. > > > CHEMISTRY@ccl.net -- To Everybody | CHEMISTRY-REQUEST@ccl.net -- > To Admins Ftp: ftp.ccl.net | WWW: http://www.ccl.net/chemistry/ | > Jan: jkl@ccl.net > > Michael J. Zehe > (216) 433-5833 Best Regards Prof. W.R. Smith Mathematics and Statistics, and School of Engineering Un. of Guelph, Guelph ON N1G2W1 Canada Tel: 519-824-4120, x6557 FAX: 519-837-0221 http://www.mathstat.uoguelph.ca/faculty/smith From chemistry-request@server.ccl.net Sun Aug 25 19:25:12 2002 Received: from ivory.trentu.ca ([192.75.12.103]) by server.ccl.net (8.11.6/8.11.0) with ESMTP id g7PNPCr06813 for ; Sun, 25 Aug 2002 19:25:12 -0400 Received: from trentu.ca ([206.248.117.30]) by trentu.ca (PMDF V5.2-32 #37862) with ESMTP id <01KLQ5DE5AI200092S@trentu.ca> for chemistry@ccl.net; Sun, 25 Aug 2002 19:25:00 EDT Date: Sun, 25 Aug 2002 19:27:13 -0400 From: elewars Subject: size consistent AND variational To: chemistry@ccl.net Message-id: <3D6967D1.1862B47A@trentu.ca> MIME-version: 1.0 X-Mailer: Mozilla 4.79 [en] (WinNT; U) Content-type: text/plain; charset=us-ascii Content-transfer-encoding: 7bit X-Accept-Language: en 2002 Aug 25 Hello, Does anyone know of a method (correlation level, like HF, MP, CI, CASSCF, etc.) besides HF and full CI that is both size consistent AND variational? Thanks. E. Lewars ===================