From owner-chemistry@ccl.net Thu Jan 7 01:31:00 2010 From: "Amir Taghavi amirtaghavi]|[khayam.ut.ac.ir" To: CCL Subject: CCL: The most significant text books in Molecular Dynamics simulation Message-Id: <-41008-100107012902-25542-IjGPtZdnRh5hn9Pq31LHhA{:}server.ccl.net> X-Original-From: "Amir Taghavi" Date: Thu, 7 Jan 2010 01:28:57 -0500 Sent to CCL by: "Amir Taghavi" [amirtaghavi : khayam.ut.ac.ir] Hi, Please give me a list of at least 5 most significant text books in Molecular Dynamics simulation. Best From owner-chemistry@ccl.net Thu Jan 7 04:54:01 2010 From: "Herbert Fruchtl herbert.fruchtl::st-andrews.ac.uk" To: CCL Subject: CCL:G: Plane wave basis sets Message-Id: <-41009-100107045027-6816-r1xM0PObESvsYnftDmXmiw##server.ccl.net> X-Original-From: Herbert Fruchtl Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1; format=flowed Date: Thu, 07 Jan 2010 09:49:50 +0000 MIME-Version: 1.0 Sent to CCL by: Herbert Fruchtl [herbert.fruchtl]=[st-andrews.ac.uk] With that email address you should know these things :-). Diffuse functions address a problem that doesn't exist with plane waves: Localised atom-centred basis sets cannot describe electrons far away from any atom. Plane waves fill space completely. Polarization functions allow the description of wavefunctions that are less symmetric than the atom. One could argue (with more hand-waving than mathematics) that the need for polarization functions implies a less smooth electron distribution, which you would address with a higher energy cutoff if you used plane waves. The only comparison I know of is the following: J. Chem. Phys. 127, 154102 (2007) It doesn't address the transition metals you are aiming at. You probably have to compare the basis set convergence between the two methods for a simple model compound. But since you should converge your cutoff before doing a serious PW calculation anyway, the GTO calculation will make little difference. HTH, Herbert Sanjay Bharathwaj computationalchemist]|[gmail.com wrote: > Dear all, > > I have a very preliminary question. > > Polarization functions and diffusion functions are added in > the Gaussian basis sets to > better describe the atomic orbitals. > > How this kind of functions could be accounted with plane wave basis sets. > Does increasing the the energy cutoff takes care of these functions. > If so what energy cut off level should be used for 4d and 5f orbitals. > > Pointing to any papers or webpages is really appreciated > > Again sorry if the question is too naive. > > Best regards > > > -- > Regards, > Dr. Sanjay Bharathwaj Kumar, > Dharmendra Institute of Technology, > Senchillakamani, > India. -- Herbert Fruchtl Senior Scientific Computing Officer School of Chemistry, School of Mathematics and Statistics University of St Andrews -- The University of St Andrews is a charity registered in Scotland: No SC013532 From owner-chemistry@ccl.net Thu Jan 7 07:57:00 2010 From: "Mudit Dixit dixitmuditk-.-gmail.com" To: CCL Subject: CCL:G: Plane wave basis sets Message-Id: <-41010-100107064651-26312-zKKvkgJAo8gPJUTglczaSw * server.ccl.net> X-Original-From: Mudit Dixit Content-Type: multipart/alternative; boundary=0016e6d5667ac4638f047c90d08a Date: Thu, 7 Jan 2010 16:18:46 +0530 MIME-Version: 1.0 Sent to CCL by: Mudit Dixit [dixitmuditk%x%gmail.com] --0016e6d5667ac4638f047c90d08a Content-Type: text/plain; charset=ISO-8859-1 Dear sanjay, To truncate the Plane wave cutoff of kinetic energy has to be chosen (that cut-off varies, for high quality calculations it should be 33% higher than you ENMAX for pseudo-potentials ) Applying higher cut-off increase the number of plane waves in the basis set (as more high kinetic energy waves are taken in the basis function) thus these wave will be able to reflect orbitals type character(Diffused 0r Polarized) . With Best Regards, Mudit Dixit JRF c/o Dr. Saurav Pal Physical Chemistry Division, Center For Excellence in Advance Computing ESTG, NCL PUNE, Ext:2298 Ph: +91-9762103575 On Tue, Jan 5, 2010 at 11:53 PM, Sanjay Bharathwaj computationalchemist]|[ gmail.com wrote: > Dear all, > > I have a very preliminary question. > > Polarization functions and diffusion functions are added in > the Gaussian basis sets to > better describe the atomic orbitals. > > How this kind of functions could be accounted with plane wave basis sets. > Does increasing the the energy cutoff takes care of these functions. > If so what energy cut off level should be used for 4d and 5f orbitals. > > Pointing to any papers or webpages is really appreciated > > Again sorry if the question is too naive. > > Best regards > > > -- > Regards, > Dr. Sanjay Bharathwaj Kumar, > Dharmendra Institute of Technology, > Senchillakamani, > India. > --0016e6d5667ac4638f047c90d08a Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Dear sanjay,
To truncate the Plane wave cutoff of kinetic energy has to = be chosen (that cut-off varies, for high quality calculations it should be = 33% higher than you ENMAX for pseudo-potentials )
Applying higher cut-o= ff increase the number of plane waves in the basis set (as more high kineti= c energy waves are taken in the basis function) thus these wave will be abl= e to reflect orbitals type character(Diffused 0r Polarized) .
With Best Regards,


Mudit Dixit
JRF
c/o Dr. Saurav Pal
P= hysical Chemistry Division,
Center For Excellence in Advance ComputingESTG,
NCL PUNE,
Ext:2298
Ph: +91-9762103575 =A0 =A0 =A0 =A0


On Tue, Jan 5, 2010 at 11:53 PM, Sanjay = Bharathwaj computationalchemist]|[gmail.com <owner-ch= emistry~!~ccl.net> wrote:
Dea= r all,=A0

I have a very preliminary question.=A0

Polarization functio= ns and diffusion functions are added in the=A0Gaussian=A0basis sets to=A0
better describe the atomic orbitals.

How this kind of fun= ctions could be accounted with plane wave basis sets.
Does increasing the the energy cutoff takes care of thes= e functions.
If so what energy cut off level should b= e used for 4d and 5f orbitals.=A0

Pointing to any pape= rs or webpages is really appreciated

Again sorry if the question is too n= aive.=A0

Best regards=A0


--
Regards,
Dr. Sanjay Bharath= waj Kumar,
Dharmendra Institute of Technology,
Senchillakamani= ,
India.

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