From owner-chemistry@ccl.net Wed Dec 6 03:23:01 2023 From: "Tian Lu sobereva~!~sina.com" To: CCL Subject: CCL: Calculation of Gibbs energies of molecules with small frequen Message-Id: <-55047-231206032112-7871-2JdGlvhphhFByyZDIPJH4g,,server.ccl.net> X-Original-From: "Tian Lu" Date: Wed, 6 Dec 2023 03:21:09 -0500 Sent to CCL by: "Tian Lu" [sobereva]*[sina.com] Hello, It is noteworthy that, aside from the well-known Truhlar's and Grimme's QRRHO treatments, in J. Comput. Chem., 44, 1807 (2023) Minenkov et al. proposed another QRRHO model, which not only applies the interpolation to entropy like Grimme's model, but also to vibrational thermal correction to internal energy, thus leading to a more consistent treatment of low-frequency contribution. Also in this work, it is shown that the interpolation treatment works much better than simply raising all low-frequencies to 100 cm^-1. Truhlar's, Grimme's and Minenkov's QRRHO models have been implemented in Shermo code (Comput. Theor. Chem., 1200, 113249 (2021)), which is freely accessible at http://sobereva.com/soft/shermo. In the appendix of Shermo manual, the three models are reviewed, references and working equations are given, hope it's helpful. Best regards, Tian Lu ------------ Sent to CCL by: Grigoriy Zhurko [reg_zhurko---chemcraftprog.com] I have implemented in my program Chemcraft a tool for computing the vibrational entropies and total Gibbs energies of molecules with small frequencies, using the frequencies threshold: all frequencies smaller than e.g. 100 cm-1 become 100 cm-1, so that the anharmonic effects which spoil the total entropy become less. I found that with this approach, the results agree better with the experiment, but currently I am unable to publish these results. And I have a stupid problem: I dont remember what to cite for confirming the applicability of this approach (the help of low frequencies threshold). I remember that I had read about this somewhere, but I dont remember when. Can you provide such a citation? Another question what approaches alternative to this exist, and whether they are better. I have heard that Orca uses QRRHO approach; I have also watched the article of Grimme and Pracht who provided one more formula for small frequencies; probably this is called msRRHO. These are not the same approach? How good they are in comparison to applying a simple threshold? Grigoriy Zhurko From owner-chemistry@ccl.net Wed Dec 6 09:37:00 2023 From: "David Shobe shobedavid:_:gmail.com" To: CCL Subject: CCL: Born-Oppenheimer breakdown test Message-Id: <-55048-231206092617-18098-1NpVyeR8uxG7t+Kp4DkMRA/./server.ccl.net> X-Original-From: David Shobe Content-Type: multipart/alternative; boundary="00000000000095a4d2060bd82100" Date: Wed, 6 Dec 2023 08:25:53 -0600 MIME-Version: 1.0 Sent to CCL by: David Shobe [shobedavid-,-gmail.com] --00000000000095a4d2060bd82100 Content-Type: text/plain; charset="UTF-8" A few years ago on this list, there was a discussion about systems in which the Born-Oppenheimer approximation is not good. H4 in a regular tetrahedral configuration was an example. Is there a way to test for breakdown of the Born-Oppenheimer approximation in a system being treated computationally? Regards and Happy Holidays, --David Shobe --00000000000095a4d2060bd82100 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
A few years=C2=A0ago on this list, there was a discussion = about systems in which the Born-Oppenheimer approximation is not good. H4 i= n a regular=C2=A0tetrahedral configuration=C2=A0was an example.=C2=A0
<= br>
Is there a way to test for breakdown of the Born-Oppenheimer = approximation in a system being treated computationally?

Regards and Happy Holidays,
--David Shobe

--00000000000095a4d2060bd82100-- From owner-chemistry@ccl.net Wed Dec 6 11:57:01 2023 From: "Jean-Pierre DJUKIC djukic]_[unistra.fr" To: CCL Subject: CCL: Calculation of Gibbs energies of molecules with small frequencies Message-Id: <-55049-231206112416-19306-taquGaRCuZgQZdOp2wtNPA~~server.ccl.net> X-Original-From: Jean-Pierre DJUKIC Content-Language: fr Content-Type: multipart/alternative; boundary="------------x8F9MSArshZK0ttvF0aV5LJz" Date: Wed, 6 Dec 2023 17:23:53 +0100 MIME-Version: 1.0 Sent to CCL by: Jean-Pierre DJUKIC [djukic()unistra.fr] This is a multi-part message in MIME format. --------------x8F9MSArshZK0ttvF0aV5LJz Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Hello, In ADF 2023, the correction described here below=C2=A0 is applied=C2=A0 o= n any=20 vibnl mode calculations and delivers in my opinion very little=20 correction to the TS value in many cases. At least it is implemented by default as far as I can infer from a=20 typical output file and no special command is required; the default=20 configuration holds: Dampener freq: 100 1/cm Dampener Alpha: 4 Averaging Moment of Inertia: 1.00E-44 kg m2. I guess we can't change much to it, right ? or is it possible to modify=20 those parameters ? Can someone validate ? JP >> To answer the part about qRRHO in ORCA and msRRHO: >> They are the same thing. They refer to an interpolation of the vibrati= onal entropy of the harmonic oscillator with the entropy of a free rotor = and was first presented in >> Grimme, S. (2012), Chem.Eur.J., 18, 9955-9964.https://doi.org/10.1002/= chem.201200497 --=20 +++++++++ Directeur de Recherche au CNRS Directeur du Laboratoire de Chimie et Syst=C3=A9mique Organom=C3=A9talliq= ues *|*UMR 7177 - Institut de Chimie de Strasbourg 4 rue Blaise Pascal 67000 Strasbourg Cedex https://orcid.org/0000-0003-3196-4921 ++++++++++++++++++++ =E2=80=9COpen as many windows as possible on the unforeseen=E2=80=9D Fr=C3=A9d=C3=A9ric Joliot-Curie "Une intuition ne se prouve pas, elle s'exp=C3=A9rimente." Gaston Bachelard ++++++++++++++++++++ --------------x8F9MSArshZK0ttvF0aV5LJz Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

Hello,

In ADF 2023, the correction described here below=C2=A0 is applied=C2= =A0 on any vibnl mode calculations and delivers in my opinion very little correction to the TS value in many cases.

At least it is implemented by default as far as I can infer from a typical output file and no special command is required; the default configuration holds:

Dampener freq: 100 1/cm

Dampener Alpha: 4

Averaging Moment of Inertia: 1.00E-44 kg m2.

I guess we can't change much to it, right ? or is it possible to modify those parameters ?

Can someone validate ?

JP



      

        
To answer the part about q=
RRHO in ORCA and msRRHO:
They are the same thing. They refer to an interpolation of the vibrationa=
l entropy of the harmonic oscillator with the entropy of a free rotor and=
 was first presented in
Grimme, S. (2012), Chem.Eur.J., 18, 9955-9964. https://doi.org/=
10.1002/chem.201200497


      

      

    

    
--=20
+++++++++
Directeur de Recherche au CNRS
Directeur du Laboratoire de Chimie et Syst=C3=A9mique Organom=C3=A9talliq=
ues
*|*UMR 7177 - Institut de Chimie de Strasbourg
4 rue Blaise Pascal
67000 Strasbourg Cedex
https://orcid.org/0000-0003-3196-4921

++++++++++++++++++++
=E2=80=9COpen as many windows as possible on the unforeseen=E2=80=9D
Fr=C3=A9d=C3=A9ric Joliot-Curie

"Une intuition ne se prouve pas, elle s'exp=C3=A9rimente."
Gaston Bachelard
++++++++++++++++++++

  


--------------x8F9MSArshZK0ttvF0aV5LJz--


From owner-chemistry@ccl.net Wed Dec  6 12:32:01 2023
From: "Marcel Swart marcel.swart~!~gmail.com" 
To: CCL
Subject: CCL: Born-Oppenheimer breakdown test
Message-Id: <-55050-231206112845-21291-JaY1wOdkPyzWiJTs1C4UKA(_)server.ccl.net>
X-Original-From: Marcel Swart 
Content-Type: multipart/alternative;
	boundary="Apple-Mail=_C0C793AE-E78E-4168-A515-26FB61E1F4BD"
Date: Wed, 6 Dec 2023 17:28:25 +0100
Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3774.200.91.1.1\))


Sent to CCL by: Marcel Swart [marcel.swart{}gmail.com]

--Apple-Mail=_C0C793AE-E78E-4168-A515-26FB61E1F4BD
Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain;
	charset=utf-8

I think this one will be of interest:
=
https://chemrxiv.org/engage/chemrxiv/article-details/65267219bda59ceb9a558=
b28
(recently accepted in JACS)

> On 6 Dec 2023, at 15:25, David Shobe shobedavid:_:gmail.com =
 wrote:
>=20
> A few years ago on this list, there was a discussion about systems in =
which the Born-Oppenheimer approximation is not good. H4 in a regular =
tetrahedral configuration was an example.=20
>=20
> Is there a way to test for breakdown of the Born-Oppenheimer =
approximation in a system being treated computationally?
>=20
> Regards and Happy Holidays,
> --David Shobe
>=20


Marcel Swart
ICREA Professor at University of Girona

IQCC (Univ. Girona)
Campus Montilivi (Ci=C3=A8ncies)
c/ M.A. Capmany, 69
17003 Girona, Spain

www.marcelswart.eu
marcel.swart]_[gmail.com

Disclaimer:
I completely understand if you don't have time to work on this until =
normal business hours. I won't be expecting an immediate response.


--Apple-Mail=_C0C793AE-E78E-4168-A515-26FB61E1F4BD
Content-Transfer-Encoding: quoted-printable
Content-Type: text/html;
	charset=utf-8

I think this =
one will be of interest:
https://chemrxiv.org/engage/chemrxiv/article-details/65267219=
bda59ceb9a558b28
(recently accepted in =
JACS)

On 6 Dec 2023, at =
15:25, David Shobe shobedavid:_:gmail.com =
<owner-chemistry]_[ccl.net> wrote:

A few =
years ago on this list, there was a discussion about systems in =
which the Born-Oppenheimer approximation is not good. H4 in a =
regular tetrahedral configuration was an =
example. 

Is there a way to test for breakdown =
of the Born-Oppenheimer approximation in a system being treated =
computationally?

Regards and Happy =
Holidays,
--David Shobe







Marcel Swart
ICREA Professor at =
University of Girona

IQCC (Univ. Girona)
Campus Montilivi (Ci=C3=A8ncies)
c/ M.A. =
Capmany, 69
17003 Girona, Spain

www.marcelswart.eu
marcel.swart]_[gmail.com

Disclaimer:
I completely understand if you don't have time to work on this until normal business hours. I won't be expecting an immediate response.




=

--Apple-Mail=_C0C793AE-E78E-4168-A515-26FB61E1F4BD--