From owner-chemistry@ccl.net Mon Nov 20 01:10:00 2017 From: "Ahmed Saeed ahmed_said5899- -yahoo.com" To: CCL Subject: CCL:G: Calculation of solution viscosity Message-Id: <-53069-171120010832-28523-m839QZPlYWvEolF0r2bfLQ]_[server.ccl.net> X-Original-From: "Ahmed Saeed" Date: Mon, 20 Nov 2017 01:08:31 -0500 Sent to CCL by: "Ahmed Saeed" [ahmed_said5899!=!yahoo.com] Dear CCL subscribers, Does anyone know a method for calculating the viscosity of a solution using Gaussian 09? Regards, Ahmed From owner-chemistry@ccl.net Mon Nov 20 03:13:00 2017 From: "Josh Berryman josh.berryman|,|uni.lu" To: CCL Subject: CCL: Calculation of solution viscosity Message-Id: <-53070-171120030735-32221-6EzMuIDat9IbTSE1t7eSYg\a/server.ccl.net> X-Original-From: "Josh Berryman" Date: Mon, 20 Nov 2017 03:07:32 -0500 Sent to CCL by: "Josh Berryman" [josh.berryman()uni.lu] Ahmed, Finding viscosities is quite tricky as the correlation functions involved have long tails, which need to be fully sampled. I would advise you to either get out a pen & paper to make an approximate analytical solution, or else get yourself organised for a significant undertaking. This has been the nemesis of at least one graduate student that I know. Allen & Tildesley's book is online (or the first ed is, anyway) to give you an overview of the theory and practice for finding viscosity via Green-Kubo method or via the Helfand moment. You will need to formulate a classical model, and to run your model I can recommend EspressoMD as a (free) classical MD code which can carry out the sampling while the code is running, to save the expensive step of post-processing to find correlation functions. The EspressoMD documentation can give you some more practical tips here. EspressoMD also has the benefit of offering NEMD (with or without Lees-Edwards boundary conditions), if you want to take the route of imposing shear flow and measuring the response, rather than the more basic technique of passively waiting for shear fluctuations and measuring their correlation functions. Dr Josh Berryman Uni Luxembourg From owner-chemistry@ccl.net Mon Nov 20 07:20:00 2017 From: "j j robinson jameschums]~[yahoo.com" To: CCL Subject: CCL: Calculation of solution viscosity - qspr ? Message-Id: <-53071-171120071812-20588-vOntKgbH9IhzCLCLAAiPoA .. server.ccl.net> X-Original-From: j j robinson Content-Type: multipart/alternative; boundary="----=_Part_1516817_78065119.1511180238942" Date: Mon, 20 Nov 2017 12:17:18 +0000 (UTC) MIME-Version: 1.0 Sent to CCL by: j j robinson [jameschums . yahoo.com] ------=_Part_1516817_78065119.1511180238942 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi Ahmed and CClers, Viscosity.. um..interesting.. would you perhaps be better off getting some = empirical data and build a QSPR model with PLS or similar or would this be = too inaccurate?=20 J J Robinson - personal email - opinions are personal only.=20 On Monday, 20 November 2017, 11:12:16 CET, Josh Berryman josh.berryman|= ,|uni.lu wrote: =20 =20 =20 Sent to CCL by: "Josh=C2=A0 Berryman" [josh.berryman()uni.lu] Ahmed, Finding viscosities is quite tricky as the correlation functions involved h= ave long tails, which need to be fully sampled.=C2=A0 I would advise you to= either get out a pen & paper to make an approximate analytical solution, o= r else get yourself organised for a significant undertaking.=C2=A0 This has= been the nemesis of at least one graduate student that I know. Allen & Tildesley's book is online (or the first ed is, anyway) to give you= an overview of the theory and practice for finding viscosity via Green-Kub= o method or via the Helfand moment. You will need to formulate a classical model, and to run your model I can r= ecommend EspressoMD as a (free) classical MD code which can carry out the s= ampling while the code is running, to save the expensive step of post-proce= ssing to find correlation functions.=C2=A0 The EspressoMD documentation can= give you some more practical tips here. EspressoMD also has the benefit of offering NEMD (with or without Lees-Edwa= rds boundary conditions), if you want to take the route of imposing shear f= low and measuring the response, rather than the more basic technique of pas= sively waiting for shear fluctuations and measuring their correlation funct= ions. Dr Josh Berryman Uni Luxembourg -=3D This is automatically added to each message by the mailing script =3D-=C2=A0 =C2=A0 =C2=A0=C2=A0 =C2=A0 =C2=A0Subscribe/Unsubscribe:=20 =C2=A0 =C2=A0 =C2=A0Job: http://www.ccl.net/jobs=20=C2=A0 =C2=A0 =C2=A0=20 ------=_Part_1516817_78065119.1511180238942 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Hi Ahmed and CClers,
<= div>
Viscosity.. um..interesting.. would you perhaps be bette= r off getting some empirical data and build a QSPR model with PLS or simila= r or would this be too inaccurate?

J J Robinson - personal email - opinions are personal = only.


=20
=20
On Monday, 20 November 2017, 11:12:16 CET, Josh Ber= ryman josh.berryman|,|uni.lu <owner-chemistry(_)ccl.net> wrote:



Sent t= o CCL by: "Josh  Berryman" [josh.berryman()uni.lu]
Ahmed,

Findin= g viscosities is quite tricky as the correlation functions involved have lo= ng tails, which need to be fully sampled.  I would advise you to eithe= r get out a pen & paper to make an approximate analytical solution, or = else get yourself organised for a significant undertaking.  This has b= een the nemesis of at least one graduate student that I know.

Allen & Tildesley's book is onl= ine (or the first ed is, anyway) to give you an overview of the theory and = practice for finding viscosity via Green-Kubo method or via the Helfand mom= ent.

You will need to = formulate a classical model, and to run your model I can recommend Espresso= MD as a (free) classical MD code which can carry out the sampling while the= code is running, to save the expensive step of post-processing to find cor= relation functions.  The EspressoMD documentation can give you some mo= re practical tips here.

EspressoMD also has the benefit of offering NEMD (with or without Lees-Ed= wards boundary conditions), if you want to take the route of imposing shear= flow and measuring the response, rather than the more basic technique of p= assively waiting for shear fluctuations and measuring their correlation fun= ctions.

Dr Josh Berrym= an
Uni Luxembourg

<= /div>


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