From owner-chemistry&$at$&ccl.net Thu Sep 8 20:27:50 2005 From: "CCL" To: CCL Subject: CCL: need the free energy values of water species Message-Id: <-29107-050908180011-13263-IkdSsI0o7bIbaeY2FfAFuw]![server.ccl.net> X-Original-From: "luo" Content-Type: multipart/alternative; boundary="----=_NextPart_000_0008_01C5B49A.1EF71640" Date: Thu, 8 Sep 2005 17:24:08 -0400 MIME-Version: 1.0 Sent to CCL by: "luo" [luo]![marine.usf.edu] This is a multi-part message in MIME format. ------=_NextPart_000_0008_01C5B49A.1EF71640 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Dear CCLs, I collected thermodynamic data you required. This new database, = "Comprehensive Handbook of Chemical Bond Energies", will be published by = CRC Press 2006. I would show you the detailed values in advance if you need some.=20 Yu-Ran Luo, Ph.D. luo]![marine.usf.edu =3D=3D=3D=3D ----- Original Message -----=20 From: CCL=20 To: Luo, Yu-Ran =20 Sent: Thursday, September 08, 2005 2:33 PM Subject: CCL: need the free energy values of water species The recentt discussion of thermodynamic quantities for water, the = proton, etc., in aqueous solution prompts me to offer a caveat to the = experimental numbers that have so far been listed. Each number that I have seen from the list thus far has LACKED any = specification of standard state. This is a common flaw in the published = literature, too (and a less understandable one since we are not talking = about quick email messages) and can introduce fairly large errors if = thermodynamic cycles are constructed without careful attention to common = standard states. I and several coauthors published a paper recently in J. Chem. Ed. = discussing the standard-state issue in some detail, and moreover = providing what we consider to be the best consensus assignment of the = free energy of solvation of the proton (which is equivalent to defining = the absolute potential of the normal hydrogen electrode, incidentally). = That reference is Lewis, A.; Bumpus, J. A.; Truhlar, D. G.; Cramer, C. J. "Molecular = Modeling of Environmentally Important Processes: Reduction Potentials" = J. Chem. Ed. 2004, 81, 596. I suspect that it would violate copyright agreement for me to attach = that article to this email, but for those who do not have access to the = journal, I would be happy to reply to personal requests for reprints (as = a pdf). I also note that an erratum has been submitted that indicates = that even after all our efforts, we too made a small standard-state, = ahem..., error. It turns out that we were lucky, because our error was = essentially exactly equal to the difference between the best estimate at = the time and a better estimate that subsequently appeared (so that we = regard all numbers in the published paper to still be correct), but it = illustrates just how tricky the standard-state issue can sometimes be. = The erratum has not yet appeared, and I'd be happy to send a preprint of = that, too, but note again that the bottom line is that the published = article contains only correct data -- the issue is more one of = discussion. Chris Cramer P.S. In the 1 atm (gas) to 1 M (aq) standard state, the free energy of = solvation for the proton that we recommend is -1096.6 kJ/mol. The two = most recent estimates from simulation and an interpretation of = ion-cluster data (for the same standard state choice) are -1097.9 +/- = 4.2 and -1104.5 +/- 8.4 kJ/mol, respectively. See Tissandier, M. D.; = Cowen, K. A.; Feng, W. Y.; Gundlach, E.; Cohen, M. H.; Earhart, A. D.; Coe, J. V.; Tuttle, T. R. J. Phys. Chem. A 1998, 102, 7787-7794 = and Zhan, C.-G.; Dixon, D. A. J. Phys. Chem. A 2001, 105, 11534-11540. Sent to CCL by: Laurynas Riauba [laurynas.Riauba[-]chf.vu.lt] You can get some numbers at http://webbook.nist.gov For liquid water, formation enthalpy is -285.84 kJ*mol-1, entropy = -69.96 J *mol-1*K-1 In "Smith B. J.,Calculation of aqueous proton dissociation constants = of quinoline and hydroxyquinolines : A comparison of solvation models, = Phys. Chem. Chem. Phys., 2000, 2, 5383-5388" following values are = mentioned (according a reference, data is from NIST page): "Experimental values for the proton enthalpy of formation (1530 kJ mol~1), entropy (108.95 J mol~1 K~1) and solvation Gibbs energy (1085.8 kJ mol~1)" Note: I suppose solvation Gibbs energy should have negative sign. For calculations of solvation energy you can look also at = http://www.chemistry.ohio-state.edu/~coe/Coe_review.pdf Laurynas Riauba, PhD student, Vilnius University, Vilnius, Lithuania CCL wrote: Dear all, I would like to know the experimental values of free energy of 1. Water 2. Hydronium (H3O+) ion 3. Hydroxide (OH-) ion 4. Proton (H+) in gas-phase and condensed phase (solvate-phase) If someone know, or the source that I can retrieve these values, could you please inform me. Thank you very much for your kind consideration. Best regards, Pong Jaturong jr_pk2001]![yahoo.com = Send instant messages to your online friends = http://uk.messenger.yahoo.com -- Christopher J. Cramer University of Minnesota Department of Chemistry 207 Pleasant St. SE Minneapolis, MN 55455-0431 -------------------------- Phone: (612) 624-0859 || FAX: (612) 626-2006 Mobile: (952) 297-2575 cramer]![pollux.chem.umn.edu http://pollux.chem.umn.edu/~cramer (website includes information about the textbook "Essentials of Computational Chemistry: Theories and Models, 2nd Edition") ------=_NextPart_000_0008_01C5B49A.1EF71640 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Dear CCLs,
 
I collected thermodynamic data you = required. This=20 new database, "Comprehensive Handbook of Chemical Bond = Energies", will=20 be published by CRC Press 2006.
 
I would show you the detailed values in = advance if=20 you need some.
 
Yu-Ran Luo, Ph.D.
luo]![marine.usf.edu
=3D=3D=3D=3D
----- Original Message -----
From:=20 CCL=20
Sent: Thursday, September 08, = 2005 2:33=20 PM
Subject: CCL: need the free = energy values=20 of water species

The recentt discussion of thermodynamic quantities for = water,=20 the proton, etc., in aqueous solution prompts me to offer a caveat to = the=20 experimental numbers that have so far been listed.

Each number = that I=20 have seen from the list thus far has LACKED any specification of = standard=20 state. This is a common flaw in the published literature, too (and a = less=20 understandable one since we are not talking about quick email = messages) and=20 can introduce fairly large errors if thermodynamic cycles are = constructed=20 without careful attention to common standard states.

I and = several=20 coauthors published a paper recently in J. Chem. Ed. discussing the=20 standard-state issue in some detail, and moreover providing what we = consider=20 to be the best consensus assignment of the free energy of solvation of = the=20 proton (which is equivalent to defining the absolute potential of the = normal=20 hydrogen electrode, incidentally). That reference = is

Lewis, A.; Bumpus, J. A.;=20 Truhlar, D. G.; Cramer, C. J. "Molecular Modeling of Environmentally = Important=20 Processes: Reduction Potentials" J. Chem. Ed. 2004, = 81,=20 596.

I suspect that it would violate = copyright=20 agreement for me to attach that article to this email, but for those = who do=20 not have access to the journal, I would be happy to reply to personal = requests=20 for reprints (as a pdf). I also note that an erratum has been = submitted that=20 indicates that even after all our efforts, we too made a small = standard-state,=20 ahem..., error. It turns out that we were lucky, because our error was = essentially exactly equal to the difference between the best estimate = at the=20 time and a better estimate that subsequently appeared (so that we = regard all=20 numbers in the published paper to still be correct), but it = illustrates just=20 how tricky the standard-state issue can sometimes be. The erratum has = not yet=20 appeared, and I'd be happy to send a preprint of that, too, but note = again=20 that the bottom line is that the published article contains only = correct data=20 -- the issue is more one of discussion.

Chris = Cramer

P.S. In the=20 1 atm (gas) to 1 M (aq) standard state, the free energy of solvation = for the=20 proton that we recommend is -1096.6 kJ/mol. The two most recent = estimates from=20 simulation and an interpretation of ion-cluster data (for the same = standard=20 state choice) are -1097.9 +/- 4.2 and -1104.5 +/- 8.4 kJ/mol, = respectively.=20 See Tissandier, M. D.; Cowen, K. A.; Feng, W. Y.; Gundlach, E.; Cohen, = M. H.;=20 Earhart,
A. D.; Coe, J. V.; Tuttle, T. R. J. Phys. Chem. A 1998, = 102,=20 7787-7794 and Zhan, C.-G.; Dixon, D. A. J. Phys. Chem. A 2001, 105,=20 11534-11540.


Sent to CCL by: Laurynas Riauba=20 [laurynas.Riauba[-]chf.vu.lt]
You can get some numbers at=20 http://webbook.nist.gov

For liquid water, formation enthalpy = is=20 -285.84 kJ*mol-1, entropy -69.96 J *mol-1*K-1

In "Smith B.=20 J.,Calculation of aqueous proton dissociation constants of quinoline = and=20 hydroxyquinolines : A comparison of solvation models, Phys. Chem. = Chem.=20 Phys., 2000, 2, 5383-5388" following values are mentioned (according = a=20 reference, data is from NIST page):

"Experimental values for = the=20 proton enthalpy of formation
(1530 kJ mol~1), entropy (108.95 J = mol~1=20 K~1) and solvation
Gibbs energy (1085.8 kJ mol~1)"

Note: I = suppose=20 solvation Gibbs energy should have negative sign.

For = calculations of=20 solvation energy you can look also at=20 = http://www.chemistry.ohio-state.edu/~coe/Coe_review.pdf


Lauryn= as=20 Riauba,
PhD student,
Vilnius University,
Vilnius,=20 Lithuania

CCL wrote:
Dear all,
I would like to know the experimental = values of=20 free energy of
1. Water
2. Hydronium (H3O+) ion
3. = Hydroxide=20 (OH-) ion
4. Proton (H+)
in gas-phase and condensed phase=20 (solvate-phase)
If someone know, or the source that I can = retrieve=20 these values,
could you please inform me.
Thank you very = much for=20 your kind consideration.
Best regards,
Pong=20 Jaturong
jr_pk2001]![yahoo.com=20 = <http://aa.f516.mail.yahoo.com/ym/Compose?To=3Djr_pk2001]![yahoo.com&= ;YY=3D74978&order=3Ddown&sort=3Ddate&pos=3D0>
Send=20 instant messages to your online friends=20 = http://uk.messenger.yahoo.com

--

Christ= opher=20 J. Cramer
University of Minnesota
Department of = Chemistry
207=20 Pleasant St. SE
Minneapolis, MN=20 55455-0431
--------------------------
Phone: (612) 624-0859 = || FAX:=20 (612) 626-2006
Mobile: (952)=20 = 297-2575
cramer]![pollux.chem.umn.edu
http://pollux.chem.umn.edu/~cra= mer
(website=20 includes information about the textbook "Essentials
of = Computational=20 Chemistry: Theories and Models, 2nd=20 Edition")

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