Dear Ty,

One option could be to ask= Gaussian technical support, help/./gaus= sian.com

Heribert

On Sat, Apr 27, 2019, 2:55 AM Ty Christian Balduf tybalduf###ku.edu <owne= r-chemistry/./ccl.net> wrote:

=
Sent to CCL by: "Ty Christian Balduf" [tybalduf[a]ku.edu]
Are there any electronic structure programs that print the exchange-correla= tion (XC) integrals for a given
DFT functional? These integrals are of the form <pq|w|rs>, where w is= an XC kernel specific to a given
functional and pqrs label arbitrary MOs.

I'm trying to make a Python code that can do TDHF/KS, with the prior SC= F done using an existing
electronic structure package. I have it working fine for TDHF, but TDKS req= uires these XC integrals and I
can't find any program that prints them (or the atomic orbital basis eq= uivalent). Ideally, if this option
exists in Gaussian, that would be most helpful to me, but I would be intere= sted to see if any program will
print these.

This question is also posted at the Chemistry Stack Exchange website:
https://chemistry.stackexchange.com/questions/114384/dft-exchan= ge-correlation-two-electron-integrals

Ty Balduf
tybalduf{:}ku.edu

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--000000000000a446130587a4e7a8-- From owner-chemistry@ccl.net Mon Apr 29 08:46:00 2019 From: "Muhammed Buyuktemiz mbtemiz3- -gmail.com" To: CCL Subject: CCL:G: Locating shallow local minimum geometries Message-Id: <-53717-190429084535-8043-VNKz79q+WsMDi326Fio+DQ{:}server.ccl.net> X-Original-From: "Muhammed Buyuktemiz" Date: Mon, 29 Apr 2019 08:45:33 -0400 Sent to CCL by: "Muhammed Buyuktemiz" [mbtemiz3^gmail.com] Dear CCLers, I am trying to optimize an intermediate (int) for a reaction mechanism with DFT involving oxygen attack. Part of the reaction mechanism is as follows; . TS1 -> (int) -> TS2 .. I have successfully located the transition states of both TS1 and TS2. However, I am having difficulties in the optimization of (int). I ran IRC calculations on TS1 and TS2. Both IRC calculations suggest the transition state structures are correct and IRC proceeds towards to the desired intermediate. But when I re-optimize the geometry I got from IRC calculations, they collapse to a different structure in the reaction mechanism. Should I just use the geometry found with IRC? I've tried this approach for a different intermediate/TS pair and found that the energies are not quite the same - there is a ~4 kcal/mol difference. I believe this intermediate is a minimum on a shallow potential energy surface. So I have tried the followings; -Decreased the cutoffs for the optimization, -Increased DFT integral grid points, i.e superfinegrid in Gaussian -Tried different optimization algorithms, -Used z-matrix and gave the initial connectivity by hand, -Computed force constants in each step of the optimization, But no luck. I would be happy if you share your experiences for such systems. Suggestions for reading materials would also be very helpful. Thank you, Best Regards. From owner-chemistry@ccl.net Mon Apr 29 15:36:00 2019 From: "Eric V. Patterson eric.patterson]-[stonybrook.edu" To: CCL Subject: CCL: Locating shallow local minimum geometries Message-Id: <-53718-190429152429-29978-Kj36zkU2ETkJlSuj6PBp4g]_[server.ccl.net> X-Original-From: "Eric V. Patterson" Content-Type: multipart/alternative; boundary="Apple-Mail=_FCFCE34A-8B49-40E4-96A9-496CA109CFAD" Date: Mon, 29 Apr 2019 15:24:21 -0400 Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.8\)) Sent to CCL by: "Eric V. Patterson" [eric.patterson/./stonybrook.edu] --Apple-Mail=_FCFCE34A-8B49-40E4-96A9-496CA109CFAD Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 Dear Muhammed, > On Apr 29, 2019, at 8:45 AM, Muhammed Buyuktemiz mbtemiz3- -gmail.com = wrote: >=20 > But when I re-optimize the geometry I got from IRC=20 > calculations, they collapse to a different structure in the reaction=20= > mechanism. How different are the structures? Relatively small differences are to = be expected. How are you judging this to be a different structure in = the reaction mechanism? > Should I just use the geometry found with IRC?=20 No. The structures from IRCs are not fully-optimized stationary points = (except maybe in rare cases when the IRC stops perfectly at the = stationary point). > I've tried this approach for a different intermediate/TS pair and = found=20 > that the energies are not quite the same - there is a ~4 kcal/mol=20 > difference. =20 That is a very small difference, and quite reasonable for the difference = between a =E2=80=9Cfinished=E2=80=9D IRC structure and the actually = stationary point. If you have a very flat PES and the optimization is indeed taking you = away from the desired minimum, I would recommend adding maxstep=3D1 to = your opt keywords; i.e. opt=3D(maxstep=3D1,=E2=80=A6,=E2=80=A6). This = reduces the step size to the minimum value (which is 1/30th of the = default step size). I have found this to be quite helpful in locating = stationary points on flat surfaces. You may need to combine it with = those other things you=E2=80=99ve already tried (finer grid, calcall, = etc). Cheers, 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 --Apple-Mail=_FCFCE34A-8B49-40E4-96A9-496CA109CFAD Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 Dear = Muhammed,

On Apr 29, 2019, at 8:45 AM, = Muhammed Buyuktemiz mbtemiz3- -gmail.com <owner-chemistry-,-ccl.net> wrote:

But when I re-optimize the = geometry I got from IRC
calculations, they collapse to a = different structure in the reaction
mechanism. =

How different are = the structures? Relatively small differences are to be expected. = How are you judging this to be a different structure in the = reaction mechanism?

Should I just use the geometry = found with IRC?

No. The = structures from IRCs are not fully-optimized stationary points (except = maybe in rare cases when the IRC stops perfectly at the stationary = point).

I've tried this approach for a different intermediate/TS pair = and found
that the energies are not quite = the same - there is a ~4 kcal/mol
difference. =

That is a very = small difference, and quite reasonable for the difference between a = =E2=80=9Cfinished=E2=80=9D IRC structure and the actually stationary = point.

If you have a very flat PES = and the optimization is indeed taking you away from the desired minimum, = I would recommend adding maxstep=3D1 to your opt keywords; i.e. = opt=3D(maxstep=3D1,=E2=80=A6,=E2=80=A6). This reduces the step = size to the minimum value (which is 1/30th of the default step size). = I have found this to be quite helpful in locating stationary = points on flat surfaces. You may need to combine it with those = other things you=E2=80=99ve already tried (finer grid, calcall, = etc).

Cheers,

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

= --Apple-Mail=_FCFCE34A-8B49-40E4-96A9-496CA109CFAD--