From owner-chemistry@ccl.net Fri Oct 11 15:16:00 2019 From: "Abrash, Samuel sabrash*richmond.edu" To: CCL Subject: CCL: aug vs jul vs jun vs may Message-Id: <-53855-191011151412-8014-hiLbiPL/uBfX6snktFTInw]*[server.ccl.net> X-Original-From: "Abrash, Samuel" Content-Language: en-US Content-Type: multipart/alternative; boundary="_000_BN7PR13MB24504DA26CEA11E8F3109C19C0970BN7PR13MB2450namp_" Date: Fri, 11 Oct 2019 19:14:04 +0000 MIME-Version: 1.0 Sent to CCL by: "Abrash, Samuel" [sabrash*|*richmond.edu] --_000_BN7PR13MB24504DA26CEA11E8F3109C19C0970BN7PR13MB2450namp_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hi Folks, I'm doing some work on systems of water clusters with other fine particulat= e matter constituents and have been using aug-cc-pVTZ as my basis set. It = was recommended to me that I try may, jun or jul-cc-pVTZ to save on calcula= tion time. I tried them for a test set of calculations and found that may = was too far off the aug results but jun and jul were pretty good. My question is why are jun and jul working? Jun omits augmented functions = on the hydrogen atoms, and I would have thought that those would be critica= l for hydrogen bonding systems. Any enlightenment would be most welcome. Thanks! Sam Abrash Samuel A. Abrash Associate Professor, Department of Chemistry University of Richmond sabrash/./richmond.edu Cell: (804) 363-2597 www.richmond.edu/~sabrash "A wise man knows for himself as much as is required, but the man of discer= nment apprehends the whole, knowing both his own point of view and that of = others...He apprehends the lower world and the upper world, his own being a= nd the being of others." The Zohar. --_000_BN7PR13MB24504DA26CEA11E8F3109C19C0970BN7PR13MB2450namp_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Hi Folks,

I’m doing some work on systems of water cluste= rs with other fine particulate matter constituents and have been using aug-= cc-pVTZ as my basis set. It was recommended to me that I try may, jun= or jul-cc-pVTZ to save on calculation time. I tried them for a test set of calculations and found that may was too far= off the aug results but jun and jul were pretty good.

My question is why are jun and jul working? Ju= n omits augmented functions on the hydrogen atoms, and I would have thought= that those would be critical for hydrogen bonding systems.

Any enlightenment would be most welcome.<= /p>

Thanks!

Sam Abrash

Samuel A. Abrash

Associate Professor, Department of Chemistry

University of Richmond

sabrash/./richmond.edu

Cell: (804) 363-2597

www.richmond.edu/~sa= brash

“A wise man knows for himself as much as is required, but t= he man of discernment apprehends the whole, knowing both his own point of v= iew and that of others…He apprehends the lower world and the upper world, his own being and the being of others.” T= he Zohar.

--_000_BN7PR13MB24504DA26CEA11E8F3109C19C0970BN7PR13MB2450namp_-- From owner-chemistry@ccl.net Fri Oct 11 19:29:01 2019 From: "Eric V. Patterson eric.patterson]^[stonybrook.edu" To: CCL Subject: CCL: aug vs jul vs jun vs may Message-Id: <-53856-191011192748-31328-JNU1/6xLWGBbs9RrJAwGYg-.-server.ccl.net> X-Original-From: "Eric V. Patterson" Content-Type: multipart/alternative; boundary="Apple-Mail=_388002DE-06DB-4A41-AA1E-866EED71965E" Date: Fri, 11 Oct 2019 18:27:40 -0500 Mime-Version: 1.0 (Mac OS X Mail 13.0 \(3594.4.19\)) Sent to CCL by: "Eric V. Patterson" [eric.patterson[#]stonybrook.edu] --Apple-Mail=_388002DE-06DB-4A41-AA1E-866EED71965E Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 Hi Sam, During my time with the Cramer group, we had a tongue-in-cheek rule: = Anyone who placed diffuse functions on light atoms would be keel-hauled. = Joking aside, Chris=E2=80=99 reason was that the functions on the heavy = atoms typically already describe the space that would be covered by the = diffuse functions on the light atoms. Thus, including them is a waste = of cpu time at best, and introduces linear dependency and convergence = failure at worst. I am sure that there are exceptions and cases where = diffuse functions on light atoms are necessary, but I have rarely used = them myself with no obvious ill effect, even in hydrogen-bonded systems. = I will also say that this was in the context of the Pople and = aug-cc-pVXZ basis sets in particular, so may not apply to more modern = basis sets. I hope all is well, Eric ---------------------------------------------------- Eric V. Patterson, PhD Director of Undergraduate Laboratories Senior Lecturer Stony Brook University Department of Chemistry 3400 SUNY Stony Brook, NY 11794-3400 465 Chemistry eric.patterson],[stonybrook.edu https://www.stonybrook.edu/commcms/chemistry/faculty/patterson.eric.html = = https://sites.google.com/a/stonybrook.edu/evpatterson = voice: (631) 632-7449 FAX: (631) 632-7960 > On Oct 11, 2019, at 2:14 PM, Abrash, Samuel sabrash*richmond.edu = wrote: >=20 > Hi Folks, > =20 > I=E2=80=99m doing some work on systems of water clusters with other = fine particulate matter constituents and have been using aug-cc-pVTZ as = my basis set. It was recommended to me that I try may, jun or = jul-cc-pVTZ to save on calculation time. I tried them for a test set of = calculations and found that may was too far off the aug results but jun = and jul were pretty good. > =20 > My question is why are jun and jul working? Jun omits augmented = functions on the hydrogen atoms, and I would have thought that those = would be critical for hydrogen bonding systems. > =20 > Any enlightenment would be most welcome. > =20 > Thanks! > Sam Abrash > =20 > Samuel A. Abrash > Associate Professor, Department of Chemistry > University of Richmond > sabrash*_*richmond.edu > Cell: (804) 363-2597 > www.richmond.edu/~sabrash > =E2=80=9CA wise man knows for himself as much as is required, but the = man of discernment apprehends the whole, knowing both his own point of = view and that of others=E2=80=A6He apprehends the lower world and the = upper world, his own being and the being of others.=E2=80=9D The Zohar. --Apple-Mail=_388002DE-06DB-4A41-AA1E-866EED71965E Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 Hi = Sam,

During my time = with the Cramer group, we had a tongue-in-cheek rule: Anyone who = placed diffuse functions on light atoms would be keel-hauled. = Joking aside, Chris=E2=80=99 reason was that the functions on the = heavy atoms typically already describe the space that would be covered = by the diffuse functions on the light atoms. Thus, including them = is a waste of cpu time at best, and introduces linear dependency and = convergence failure at worst. I am sure that there are exceptions = and cases where diffuse functions on light atoms are necessary, but I = have rarely used them myself with no obvious ill effect, even in = hydrogen-bonded systems. I will also say that this was in the = context of the Pople and aug-cc-pVXZ basis sets in particular, so = may not apply to more modern basis sets.

I hope all is well,

Eric

----------------------------------------------------
Eric V. Patterson, PhD

Director of Undergraduate Laboratories
Senior = Lecturer

Stony Brook University
Department of = Chemistry
3400 SUNY
Stony Brook, NY = 11794-3400

465 Chemistry
eric.patterson],[stonybrook.edu

https://www.stonybrook.edu/commcms/chemistry/faculty/patterson.= eric.html

https://sites.google.com/a/stonybrook.edu/evpatterson

voice: (631) = 632-7449
FAX: (631) 632-7960

On Oct 11, 2019, at 2:14 PM, Abrash, Samuel sabrash*richmond.edu <owner-chemistry],[ccl.net> wrote:

Hi = Folks,

I=E2=80=99m doing some work on systems of water clusters with = other fine particulate matter constituents and have been using = aug-cc-pVTZ as my basis set. It was recommended to me that I try = may, jun or jul-cc-pVTZ to save on calculation time. I tried them = for a test set of calculations and found that may was too far off the = aug results but jun and jul were pretty good.

My = question is why are jun and jul working? Jun omits augmented = functions on the hydrogen atoms, and I would have thought that those = would be critical for hydrogen bonding systems.

Any = enlightenment would be most welcome.

Thanks!
Sam Abrash

Samuel A. Abrash
Associate Professor, Department of = Chemistry
University of Richmond
sabrash*_*richmond.edu
Cell: (804) 363-2597
www.richmond.edu/~sabrash
=E2=80= =9CA wise man knows for himself as much as is required, but the man of = discernment apprehends the whole, knowing both his own point of view and = that of others=E2=80=A6He apprehends the lower world and the upper = world, his own being and the being of others.=E2=80=9D The = Zohar.

= --Apple-Mail=_388002DE-06DB-4A41-AA1E-866EED71965E--