From owner-chemistry@ccl.net Wed Aug 15 05:46:03 2007 From: "Herbert Fruchtl herbert.fruchtl,+,st-andrews.ac.uk" To: CCL Subject: CCL: Confusion about transition state Message-Id: <-34929-070815051928-21646-zbt0gDvjpDKE5NIRfk+6cQ###server.ccl.net> X-Original-From: Herbert Fruchtl Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1; format=flowed Date: Wed, 15 Aug 2007 09:50:00 +0100 MIME-Version: 1.0 Sent to CCL by: Herbert Fruchtl [herbert.fruchtl * st-andrews.ac.uk] You need one negative frequency AND a zero gradient, otherwise it is not a critical point. H. Kaci Tizi_Ouzou kaci.tiziouzou##gmail.com wrote: > Hi all, > > I think I am getting confused about the transition state calculation. > > > I always believed that a single negative frequency is a sufficient > condition for a TS. But I just noticed during a manual PES scan that I > had ONE negative frequency before reching the highest energy. > > Shall I conclude that: A negative frequency is a necessary BUT NOT a > sufficient condition for a TS? > > > Cheers > > > Kass > > -- Herbert Fruchtl EaStCHEM Fellow School of Chemistry University of St Andrews From owner-chemistry@ccl.net Wed Aug 15 05:55:00 2007 From: "Joop van Lenthe joop:-:chem.uu.nl" To: CCL Subject: CCL: Confusion about transition state Message-Id: <-34930-070815051708-10760-rzScLnB16JK1ng4xaeSNwg~!~server.ccl.net> X-Original-From: Joop van Lenthe Content-Type: multipart/alternative; boundary=Apple-Mail-1-553268551 Date: Wed, 15 Aug 2007 10:26:22 +0200 Mime-Version: 1.0 (Apple Message framework v752.2) Sent to CCL by: Joop van Lenthe [joop-x-chem.uu.nl] --Apple-Mail-1-553268551 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Yes,. you need zero gradients too. (stationary point) On Aug 13, 2007, at 18:02, Kaci Tizi_Ouzou kaci.tiziouzou##gmail.com wrote: > Hi all, > > I think I am getting confused about the transition state calculation. > > > I always believed that a single negative frequency is a sufficient > condition for a TS. But I just noticed during a manual PES scan > that I had ONE negative frequency before reching the highest energy. > > Shall I conclude that: A negative frequency is a necessary BUT NOT > a sufficient condition for a TS? > > > Cheers > > > Kass > > ========================================= Joop van Lenthe Theoretical Chemistry Group Utrecht University Padualaan 8 3584 CH Utrecht -31-30-2532733 joop^^^chem.uu.nl ========================================= --Apple-Mail-1-553268551 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 Yes,. you need zero gradients = too. (stationary point)

On Aug 13, 2007, at 18:02, Kaci = Tizi_Ouzou kaci.tiziouzou##gmail.com wrote:

Hi = all,

=A0

I think I am getting confused about the = transition state calculation.

=A0

=A0
=
I always believed that a single negative frequency is a sufficient = condition=A0for a TS. But=A0I=A0just noticed=A0during a manual PES scan = that I had ONE negative frequency before reching the highest energy. =

=A0

Shall I conclude that: A negative frequency = is a necessary BUT NOT a sufficient condition for a TS?
=
=A0

=A0

Cheers

=A0
=
=A0

Kass

=A0
=
=A0

joop^^^chem.uu.nl

=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

=

= --Apple-Mail-1-553268551-- From owner-chemistry@ccl.net Wed Aug 15 10:05:01 2007 From: "Shobe, David David.Shobe..sud-chemie.com" To: CCL Subject: CCL: Confusion about transition state Message-Id: <-34931-070815095115-22051-BtWA30TPkRyyKhhiK5KjLw__server.ccl.net> X-Original-From: "Shobe, David" Content-class: urn:content-classes:message Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C7DF43.3AC3E856" Date: Wed, 15 Aug 2007 15:50:23 +0200 MIME-Version: 1.0 Sent to CCL by: "Shobe, David" [David.Shobe _ sud-chemie.com] This is a multi-part message in MIME format. ------_=_NextPart_001_01C7DF43.3AC3E856 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable This is a generalization of what you learned in first year calculus: the maximum of a differentiable 1-variable function occurs at a point where: 1. The first derivative is zero 2. The second derivative is negative =20 Regards, --David Shobe =20 ________________________________ > From: owner-chemistry,+,ccl.net [mailto:owner-chemistry,+,ccl.net]=20 Sent: Wednesday, August 15, 2007 4:26 AM To: Shobe, David Subject: CCL: Confusion about transition state =20 Yes,. you need zero gradients too. (stationary point) On Aug 13, 2007, at 18:02, Kaci Tizi_Ouzou kaci.tiziouzou##gmail.com wrote: Hi all, =20 I think I am getting confused about the transition state calculation.=20 =20 =20 I always believed that a single negative frequency is a sufficient condition for a TS. But I just noticed during a manual PES scan that I had ONE negative frequency before reching the highest energy.=20 =20 Shall I conclude that: A negative frequency is a necessary BUT NOT a sufficient condition for a TS? =20 =20 Cheers =20 =20 Kass =20 =20 =20 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D Joop van Lenthe Theoretical Chemistry Group Utrecht University Padualaan 8 3584 CH Utrecht -31-30-2532733 joop#chem.uu.nl =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 This e-mail message may contain confidential and / or privileged informatio= n. If you are not an addressee or otherwise authorized to receive this mess= age, you should not use, copy, disclose or take any action based on this e-= mail or any information contained in the message. If you have received this= material in error, please advise the sender immediately by reply e-mail an= d delete this message.=20 Thank you. ------_=_NextPart_001_01C7DF43.3AC3E856 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

This is a generalization of what you learned in first year calculus:

the maximum of a differentiable = 1-variable function occurs at a point where:

1. The first deriva= tive is zero

2. The second deriv= ative is negative

Regards,

--David Shobe=

From: owner-chemistry,+,ccl.net [mailto:owner-chemistry,+,ccl.net]
Sent: Wednesday, August 15, = 2007 4:26 AM
To: Shobe, David
Subject: CCL: Confusion about transition state

Yes,. you need zero gradients too. (stationary point)

On Aug 13, 2007, at 18:02, Kaci Tizi_Ouzou kaci.tiziouzou##gmail.com wrote:

Hi all,

I think I am getting confused about the transition state calculatio= n.

I always believed that a single negative frequency is a sufficient condition for a TS. But I just noticed during a manual = PES scan that I had ONE negative frequency before reching the highest energy. <= o:p>

Shall I conclude that: A negative frequency is a necessary BUT NOT a sufficient condition for a TS?

Cheers

Kass

=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

Joop van Lenth= e

Theoretical Chemistry Group

Utrecht University

Padualaan 8 35= 84 CH Utrecht

-31-30-2532733=

joop#chem.uu.nl

=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

This e-mail message may contain confidential and / or privileged informatio= n. If you are not an addressee or otherwise authorized to receive this mess= age, you should not use, copy, disclose or take any action based on this e-= mail or any information contained in the message. If you have received this= material in error, please advise the sender immediately by reply e-mail an= d delete this message.
Thank you.

------_=_NextPart_001_01C7DF43.3AC3E856-- From owner-chemistry@ccl.net Wed Aug 15 11:31:01 2007 From: "Keith Butler keeeto2000..yahoo.co.uk" To: CCL Subject: CCL: solvent calc. Message-Id: <-34932-070815102657-2655-LK//S3dymCmbGoThZKchsw++server.ccl.net> X-Original-From: Keith Butler Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=iso-8859-1 Date: Wed, 15 Aug 2007 14:26:32 +0100 (BST) MIME-Version: 1.0 Sent to CCL by: Keith Butler [keeeto2000- -yahoo.co.uk] Dear Andreas, Just a follow up question to your answer. Would you suggest that to find free energy of the solvated species using an implict method that the frequency calculations should be performed in the gas phase on the SOLUTION phase geometries or on gas phase structures before applying the thermodynamic cycle. Many Thanks, Keith Butler --- "Andreas Klamt klamt:-:cosmologic.de" wrote: > > Sent to CCL by: Andreas Klamt > [klamt###cosmologic.de] > Dear Aleksandra, > > sorry to tell you that even in the case of neutral > reactions it does not > make much sense to apply the standard gasphase > methods. All the > vibrational free energy contributions are not > meaningful in the solvent. > The change in vibrational free energy from gasphase > to the solvent is > already parameterized into the solvent models (see > e.g. my CCL > contribution from 17.05.2007 ). > > In my opinion, the only reasonable way to do this in > the solvent is to > calculate the gasphase reaction and to apply > dG_solvation (from a good, > quantitative solvation model) to educts and > products., i.e. use the > thermodynamic cycle > > Educts, solv ---> Educts, gas --> Products,gas --> > Products, solv > > Andreas > > > Aleksandra Rudnitskaya aleksandra.rudnit001#umb.edu > schrieb: > > Sent to CCL by: "Aleksandra Rudnitskaya" > [aleksandra.rudnit001##umb.edu] > > Thanks a lot to everyone who sent his answer. I > realized I took a wrong example. What if I choose > the other system with benzene as a solvent? The > questions are the same - > > what should I write in input file for > optimization, and TS? > > > > > > Thank you > > > > Aleksandra > > > > > >> Dear CCL members, > >> > >> Ive just started calculations with solvent. I > decided to start from reaction of neutralization > NaOH+HCl=H2O+NaCl. As I understand I should > calculate > >> 1) optimization sodium hydroxide in solvent > (water); > >> 2) optimization hydrochloric acid in solvent; > >> 3) optimization sodium chloride in solvent; > >> 4) transition state again in solvent. > >> Idea is very similar to that when I calculate > rxns in gas phase. Is it correct? > >> When I calculate stable species without any > solvent I use > >> opt freq=noraman RHF/6-31G(d) > >> For TS calculations I use > >> RHF/6-31G(d) Opt(TS,CalcFC,noeigentest) > Freq=noraman > >> > >> and then charge and multiplicity, and simple > Z-matrix in specification part. How should input > files look for optimization and searching TS? I know > I have to use keyword SCRF, and one of those > (SCRF=Dipole, PCM, DPCM, CPCM or IEFPCM), then > specify solvent, and probably, dielectric constant > somewhere in specification part after matrix. If you > may guide me how to create input file itll help a > lot. > >> > >> Thank you very much.> > > > > > > > > > > > -- > ----------------------------------------------------------------------------- > Dr. habil. Andreas Klamt > COSMOlogic GmbH&CoKG > Burscheider Str. 515 > 51381 Leverkusen, Germany > > Tel.: +49-2171-73168-1 Fax: +49-2171-73168-9 > e-mail: klamt[A]cosmologic.de > web: www.cosmologic.de > ----------------------------------------------------------------------------- > COSMOlogic > Your Competent Partner for > Computational Chemistry and Fluid > Thermodynamics > ----------------------------------------------------------------------------- > > > > -= This is automatically added to each message by > the mailing script =- > To recover the email address of the author of the > message, please change > the strange characters on the top line to the _-_ > sign. You can also > look up the X-Original-From: line in the mail > header.> > E-mail to administrators: CHEMISTRY-REQUEST_-_ccl.net > or use> > Before posting, check wait time at: > http://www.ccl.net> Conferences: > http://server.ccl.net/chemistry/announcements/conferences/ > > Search Messages: http://www.ccl.net/htdig (login: > ccl, Password: search) > > If your mail bounces from CCL with 5.7.1 error, > check:> > RTFI: > http://www.ccl.net/chemistry/aboutccl/instructions/> > > > ___________________________________________________________ Yahoo! Answers - Got a question? Someone out there knows the answer. Try it now. http://uk.answers.yahoo.com/ From owner-chemistry@ccl.net Wed Aug 15 12:06:01 2007 From: "may abdelghani may01dz()yahoo.fr" To: CCL Subject: CCL: nonlinear optical properties Message-Id: <-34933-070815054112-25785-kdOibE7B+4aZZ2b5t0su8w*|*server.ccl.net> X-Original-From: may abdelghani Content-Transfer-Encoding: 8bit Content-Type: multipart/alternative; boundary="0-646845834-1187167262=:41474" Date: Wed, 15 Aug 2007 10:41:02 +0200 (CEST) MIME-Version: 1.0 Sent to CCL by: may abdelghani [may01dz_._yahoo.fr] --0-646845834-1187167262=:41474 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Dear CCL�ers What are the properties, which we need to calculate, and can tell us that this molecule, have (or have not) a nonlinear optical properties. thanks --------------------------------- Ne gardez plus qu'une seule adresse mail ! Copiez vos mails vers Yahoo! Mail --0-646845834-1187167262=:41474 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Dear CCL�ers
What are the properties, which we need to calculate, and can tell us that this molecule, have (or have not) a nonlinear optical properties.
thanks

Ne gardez plus qu'une seule adresse mail ! Copiez vos mails vers Yahoo! Mail --0-646845834-1187167262=:41474-- From owner-chemistry@ccl.net Wed Aug 15 14:27:01 2007 From: "Elaine Meng meng+/-cgl.ucsf.edu" To: CCL Subject: CCL: nonlinear optical properties Message-Id: <-34934-070815142425-28209-FWjdbGifqUiGdJ3XTbRuVA~~server.ccl.net> X-Original-From: "Elaine Meng" Date: Wed, 15 Aug 2007 14:24:20 -0400 Sent to CCL by: "Elaine Meng" [meng(~)cgl.ucsf.edu] Maybe take a look at NLOPredict, available from http://sda.iu.edu/nlopredict/ and described in this new paper: Moad AJ, Moad CW, Perry JM, Wampler RD, Goeken GS, Begue NJ, Shen T, Heiland R, Simpson GJ. NLOPredict: Visualization and data analysis software for nonlinear optics. J Comput Chem. 2007 Sep;28(12):1996-2002. It is a plugin to Chimera http://www.cgl.ucsf.edu/chimera/ Best, Elaine ----- Elaine C. Meng, Ph.D. meng{}cgl.ucsf.edu UCSF Computer Graphics Lab and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco http://www.cgl.ucsf.edu/home/meng/index.html From owner-chemistry@ccl.net Wed Aug 15 15:02:00 2007 From: "Jason A. Ford-Green jgreen[#]ccmsi.us" To: CCL Subject: CCL: nonlinear optical properties Message-Id: <-34935-070815135806-25503-HGgAvPI5ITmk0fZk+geSvQ^_^server.ccl.net> X-Original-From: "Jason A. Ford-Green" Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=ISO-8859-1 Date: Wed, 15 Aug 2007 12:22:40 -0500 Mime-Version: 1.0 Sent to CCL by: "Jason A. Ford-Green" [jgreen(a)ccmsi.us] I do not run calculations on possible non-linear optical polymers, however other people at our institution have done extensive work in the field. Theoretical determination is generally conducted through TD-DFT analyis of the first, second, and possibly higher hyperpolarizability constants i.e. beta, gamma etc. Calculations of hyperpolarizability-dependant tensors are directly linked, of course, to symmetry of the molecular system. Finally, Accuracy may be pendant upon which functional chosen, which utilizes various sets of approximations i.e LDA, LSDA, and GGA. CI methods should also be reviewed, but depending on your system size scaling may come into play. Computationally this may be a good starting point. Hope this helps. Jason Ford-Green Doctoral Student Computational Center for Molecular Structure & Interactions Department of Chemistry Jackson State University Cooperative Education Program Student U.S. Army Engineer Research and Development Center PI: Jerzy Leszczynski,Ph.D Cell: 850-443-9233 Lab: 601-979-1797 ---------- Original Message ---------------------------------- > From: "may abdelghani may01dz()yahoo.fr" Reply-To: "CCL Subscribers" Date: Wed, 15 Aug 2007 10:41:02 +0200 (CEST) >Dear CCL�ers >What are the properties, which we need to calculate, and can tell us that this molecule, have (or have not) a nonlinear optical properties. >thanks > > >--------------------------------- > Ne gardez plus qu'une seule adresse mail ! Copiez vos mails vers Yahoo! Mail > From owner-chemistry@ccl.net Wed Aug 15 15:36:01 2007 From: "Wendy Anne Warr wendy,warr.com" To: CCL Subject: CCL: Report on Spring 2007 ACS Meeting Message-Id: <-34936-070815150251-13852-WlpKDLEnrUOcdNqQaJA3sA_-_server.ccl.net> X-Original-From: "Wendy Anne Warr" Date: Wed, 15 Aug 2007 15:02:44 -0400 Sent to CCL by: "Wendy Anne Warr" [wendy(a)warr.com] Chemical Information and Computation 2007, Number One Report on the 233rd ACS National Meeting and Exposition, Chicago, March 25-29, 2007 The contents list is on the Web at http://www.warr.com/morepubs.html. The report includes: news from almost 80 companies (including some not exhibiting) shortened press releases for the first six months of 2007 accurate transcripts of 30 presentations, complete with color figures and literature references, with the following themes: o computer-assisted drug design, honoring Yvonne Martin (11 papers) o rational drug design (paper by Jorgensen) o de novo design coupled to synthetic feasibility (2 papers) o advances in 3D pharmacophores and 3D searching (2 papers) o advanced mining and use of life science information (6 papers) o chemical information, honoring Gary Wiggins (2 papers) o information resources (2 papers) o social networking tools (paper by Warr) o open meeting of the ACS committees on ACS Publications and CAS o MCS-based hierarchical clustering and pKa calculation (two posters). Contact me by email for further details. Wendy Dr. Wendy A. Warr Wendy Warr & Associates 6 Berwick Court, Holmes Chapel Cheshire, CW4 7HZ, England Tel./fax +44 (0)1477 533837 wendy||warr.com http://www.warr.com From owner-chemistry@ccl.net Wed Aug 15 17:16:01 2007 From: "gustavo .. mercury.chem.pitt.edu" To: CCL Subject: CCL: nonlinear optical properties Message-Id: <-34937-070815153209-1910-lxfzsBx4JtvRvjHsYVeXDg##server.ccl.net> X-Original-From: gustavo~~mercury.chem.pitt.edu Content-Transfer-Encoding: 8bit Content-Type: text/plain;charset=iso-8859-1 Date: Wed, 15 Aug 2007 13:55:00 -0400 (EDT) MIME-Version: 1.0 Sent to CCL by: gustavo(~)mercury.chem.pitt.edu > Dear CCL�ers > What are the properties, which we need to calculate, and can tell us that > this molecule, have (or have not) a nonlinear optical properties. > thanks > Hi, if you are interested in second harmonic generation or other second order properties you need to calculate the first hyperpolarizability BETA. If you want third order properties like third harmonic generation you need to calculate the second hyperpolarizability GAMMA. In the two cases mentioned you may calculate only the static hyperpolarizabilities and see if the values are large. If your molecule has inversion symmetry the value of BETA is zero. If you are interested in two photon absorption you need to calculate the imaginary part of the dynamic second hyperpolarizability and transform this into a cross section for absorption of two photons. If you have more questions please don�t hesitate to ask. Sincerelly yours, Gustavo L.C. Moura gustavo .at. mercury.chem.pitt.edu From owner-chemistry@ccl.net Wed Aug 15 19:45:00 2007 From: "Phillips, James M. PhillipsJ:+:umkc.edu" To: CCL Subject: CCL:G: Surface chemistry with a cluster model: Good references ? Message-Id: <-34938-070814182446-31170-OANW68yUcmxBgEcS8ZT1Uw]_[server.ccl.net> X-Original-From: "Phillips, James M." Content-class: urn:content-classes:message Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="us-ascii" Date: Tue, 14 Aug 2007 16:51:30 -0500 MIME-Version: 1.0 Sent to CCL by: "Phillips, James M." [PhillipsJ : umkc.edu] Tanguy: Well, you are in for quite a ride. Cluster calculations work very well for local properties, frequency, bond length and angle. The optimization of adsorption sites are in our experience very good. The big problem is the adsorption energy. The cluster size can never be big enough. Gaussian and semiemprical methods work well but the adsorption energy problem can be fixed if you can except an estimate. We use Birge-Sponer approach for Do. The last time I tried, Gaussian still does not have the PBC working well enough to be helpful. Recently, we have been using VASP with amazing results. Regards, Jim Phillips See: S. Yang, James M. Phillips, "Geometric and electronic structure of commensurate 4Ar/Ag(111)- by density functional theory." Physical Review B 75, 235408 (2007) S. Yang, James M. Phillips, L. Ouyang, "Density-functional calculations of a (1x1) and a (1x3) supported gold system: Au/TiO3/Mo(112)." Physical Review B 74, 1 (2006). S. Yang, L. Ouyang, James M. Phillips, W. Y.Ching, "Density-functional calculations of methane adsorption on graphite (0001)." Physical Review B 73, 165407 (2006). S. J. Harrington, K. Kilway, D.-M. Zhu, James M. Phillips, F. M. Leibsle, "Formate-induced destabilization of the Cu(110) Surface", Surface Science 600, 1193 (2006). Shizhong Yang, F. M. Leibsle, James M. Phillips, "Quantum chemical calculations of coupled vibrations of adsorbates: A comparative study of CO/Cu(110) and O/diamond(100)." Surface Science 2005, 579, 107-115. Phillips, James M., "A comparative study of chemisorpition by density functional theory, ab initio, and semiempirical methods: carbon monoxide, formate, and acetate on Cu(110)," Surface Science 2003, 545, 1-7. S. M. York, S. Haq, J. M. Phillips, F. M. Leibsle, "STM, FTIR, and quantum chemical calculations studies of acetate structures on Cu(110) surfaces,"Surface Science 2003, 522 34-46. -----Original Message----- > From: owner-chemistry(_)ccl.net [mailto:owner-chemistry(_)ccl.net] Sent: Tuesday, August 14, 2007 10:14 AM To: Phillips, James M. Subject: CCL:G: Surface chemistry with a cluster model: Good references ? Sent to CCL by: "Tanguy Van Regemorter" [tanguy.vr * yucom.be] Hello everybody, I am PhD student and I am working on the modelling of the chemistry at the diamond surface during the growth by chemical vapour deposition. Until now, I have perform plane wave calculations (Using the program CASTEP) but I would like to perform some cluster calculations using Gaussian. I have build different model size for the two surface orientations I am interested in (111 and 100). For the different size, I have calculated the CH3 adsorption energy in order to quantify the size effect. > From these calculation, I obtained different values for the adsorption energy but I have some problem to analyse them correctly. I tend to compare them to the values I have obtained with my plane-wave calculations but I am not sure that it is a correct way to proceed. Since this type of calculations are rather new for me, I have been looking for references or books which could help me but I seems to be rather tricky. Is there anybody who could give me some advices or good reference on this type of calculations (i.e. comparison between plane-wave and cluster calculations for surface reactivity) even if it is for different materials ? Thank you very much in advance ! Best Regards, Tanguy Van Regemorterhttp://www.ccl.net/cgi-bin/ccl/send_ccl_messagehttp://www.ccl.net/chemistry/sub_unsub.shtmlhttp://www.ccl.net/spammers.txt