From owner-chemistry@ccl.net Wed Jan 8 00:03:00 2020 From: "Robert Molt r.molt.chemical.physics{}gmail.com" To: CCL Subject: CCL: The best method to calculate the ionization potential of organic mol. Message-Id: <-53932-200107143058-10241-lpoUazLCXW5l7L+aRXywQQ**server.ccl.net> X-Original-From: Robert Molt Content-Type: multipart/alternative; boundary="Apple-Mail=_E23009D1-BC6E-4EFE-92A5-6F3EFA3516FD" Date: Tue, 7 Jan 2020 14:30:48 -0500 Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.11\)) Sent to CCL by: Robert Molt [r.molt.chemical.physics*|*gmail.com] --Apple-Mail=_E23009D1-BC6E-4EFE-92A5-6F3EFA3516FD Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 I am perhaps confused on the convention of =E2=80=9Cadiabatic.=E2=80=9D = A smart man once advised me to never use the term, since its meaning can = be ambiguous ;) I think I am using the term properly, but conventions = are useful only in so much as they make things clearer rather than less = clear. Regardless, my meaning is as I wrote in the paragraph or as Dr. = Mihailovs wrote: the geometry-relaxed ionization state corresponds to a = different ionization energy than the geometry-not-relaxed state. = Different experiments measure one or the other, but it is not correct to = say that they are different =E2=80=9Cmethods=E2=80=9D to describe the = ionization energy; they are different physical quantities, no more the = same than the Gibbs energy is the same as a spin-orbit correction. > On Jan 7, 2020, at 11:19 AM, Igors Mihailovs igorsm,cfi.lu.lv = wrote: >=20 > Dear Dr. Molt, >=20 > I was somewhat sure that "adiabatic" ionization correspond to the = relaxed geometries. You probably intended to compare "vertical" and = "adiabatic" (or "relaxed-geometry"). Or am I wrong? As far as I know the = term "adiabatic" is because there is no further energy exchange with the = environment expected because the geometry has already been relaxed. >=20 > I also would like to add my bit to the discussion with the following = points. >=20 > Adiabatic ionization energies and electron affinities are the = quantities needed to compare with experimental electrochemistry, for = example (see the Marcus equation), because the adiabatic difference is = the driving force, but the reorganization energies (difference between = the adiabatic and vertical quantities) are also involved because the = transition is vibrationally-assisted. >=20 > Also, unoccupied levels for the pure (non-hybrid) Kohn=E2=80=94Sham = roughly correspond to excitation energies rather than to electron = affinities (see, e.g., Baerends, E. J.; Gritsenko, O. V; van Meer, R. = Phys. Chem. Chem. Phys. 2013, 15 (39), 16408). This is lost when HF = admixture is introduced (as in hybrid functionals). >=20 > Also, I presume that optimally tuned range-separated hybrids are a = more or less viable alternative for the costly methods because, even if = they are tuned for every particular molecule, said generalized Koopmans' = theorem is the basis for tuning. I cannot find the article right now, = though, so I am not totally sure. For TD-DFT though, they are very good = (https://pubs.acs.org/doi/abs/10.1021/ct5000617 = ). >=20 > With hope this is not rubbish, > Igors Mihailovs >=20 > On 1/7/20 2:45 PM, Robert Molt r.molt.chemical.physics{:}gmail.com = wrote: >> 1.) Dr. Lehtola=E2=80=99s suggestion is correct. A distinction should = be made when saying that =E2=80=9CKoopmans=E2=80=99s theorem does not = hold for DFT.=E2=80=9D Whether or not =E2=80=9Cthe true=E2=80=9D DFT = should have Koopmans=E2=80=99s theorem is a subject of some scholarly = debate. Dr. Bartlett=E2=80=99s work is intended to be proof that a = well-formulated DFT, with emphasis on enforcing physical constraints, = can do this. This is meant to be in contrast to the zoo of highly = parameterized KS-DFT functionals, which do badly poorly outside their = parameterization range (the Minnesota functionals being an example which = are stupendous at many, many things, then bizarrely terrible in certain = circumstances outside the standard comp chem goals). >>=20 >> 2.) None of this is intended to argue that Dr. Bartlett=E2=80=99s = work is or is not the best you can do, accuracy -wise, right here right = now.=20 >>=20 >> 3.) The original question has a false dichotomy. The original = question compared adiabatic vs. relaxed excitations (re-optimizing the = structure of the cation or not) asking which was =E2=80=9Cmore = accurate.=E2=80=9D This is wrong; my emphasis is intended for clarity, = not to be pejorative. These correspond to two totally different = experimental situations. If you are trying to model ionization energies, = you should re-optimize the geometries iff you are comparing to = experimental ionization energies where the system=E2=80=99s molecular = geometry does have time to relax. The same is true that an adiabatic = ionization energy must be compared to an adiabatic ionization = experiment. Usually, people mean the adiabatic ionization energy if they = do not qualify what they mean (but one should specify). It would be = inconsistent to use relaxed structures to compute adiabatic ionization = energies. >>=20 >> One could argue to do this anyway, on the grounds of judicious = cancellation of error; I am ignorant, personally, of how errors cancel, = assuming a systematic error exists in the first place. However, in so = much as the goal of our field is to compute the right answer for the = right reasons, it is inconsistent. >>=20 >>> On Jan 7, 2020, at 4:08 AM, Susi Lehtola susi.lehtola[*]helsinki.fi = > wrote: >>>=20 >>>=20 >>> Sent to CCL by: Susi Lehtola [susi.lehtola a helsinki.fi = ] >>> On 1/7/20 12:26 AM, Daniel Glossman-Mitnik dglossman _ gmail.com = wrote: >>>> The Koopmans' theorem (note that it is Koopmans, not Koopman) does = not (theoretically) hold within DFT and it has been always used as = approximation. However, there is another theorem that it is valid within = Generalized Kohn-Sham model (GKS) that validates the use of E(HOMO as = -I. This does not hold for A and the LUMO, but it can be said that A is = equal to -E(HOMO) of the anion. =46rom a practical point of view, if the = E(HOMO) of the anion is equal to the E(LUMO) of the neutral, then this = counterpart of Koopmans' theorem will hold within DFT. Indeed this is an = approximation, and its accuracy will be depending on the model chemistry = chosen for your calculations. In our research group, we have been doing = investigations to find the best model chemistry that satisfies this = approximation and our published results show that the = MN12SX/Def2TZVP/H20 reproduce the values with great accuracy. Of course, = there could be another combinations that could help (including tuned = density functionals to get the desired Koopmans behavior) but most of = the usually recommended density functionals are not useful in this = regard. >>>=20 >>> Bartlett's "consistent DFT" should also be mentioned in this = context; their QTP functionals are obtained by enforcing correct = excitation spectra. See dois 10.1016/j.cplett.2016.12.017 and = 10.1063/1.5116338. >>> --=20 >>> ------------------------------------------------------------------ >>> Mr. Susi Lehtola, PhD Junior Fellow, Adjunct Professor >>> susi.lehtola() alumni.helsinki.fi = University of Helsinki >>> http://susilehtola.github.io/ = Finland >>> ------------------------------------------------------------------ >>> Susi Lehtola, dosentti, FT tutkijatohtori >>> susi.lehtola() alumni.helsinki.fi = Helsingin yliopisto >>> http://susilehtola.github.io/ >>> ------------------------------------------------------------------ >>>=20 >>>=20 >>>=20 >>>=20 >>>=20 >>> the strange characters on the top line to the /a\ sign. You can also >>>=20 >>>=20 >>> E-mail to subscribers: CHEMISTRY/a\ccl.net or use:= >>>=20 >>> E-mail to administrators: CHEMISTRY-REQUEST/a\ccl.net or use= >>>=20 >>>=20= >>>=20 = Conferences:http://server.ccl.net/chemistry/announcements/conferences/ = >>>=20= >>>=20= >>>=20= >>>=20 >>>=20 >>=20 >=20 > --=20 > Ar cie=C5=86u, > Igors Mihailovs > Zin=C4=81tniskais asistents > Organisko materi=C4=81lu laboratorija > LU Cietvielu fizikas instit=C5=ABts > Yours faithfully, > Igors Mihailovs > Research assistant > Laboratory of Organic Materials > Institute of Solid State Physics, University of Latvia --Apple-Mail=_E23009D1-BC6E-4EFE-92A5-6F3EFA3516FD Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 I = am perhaps confused on the convention of =E2=80=9Cadiabatic.=E2=80=9D A = smart man once advised me to never use the term, since its meaning can = be ambiguous ;) I think I am using the term properly, but conventions = are useful only in so much as they make things clearer rather than less = clear.

Regardless, = my meaning is as I wrote in the paragraph or as Dr. Mihailovs wrote: the = geometry-relaxed ionization state corresponds to a different ionization = energy than the geometry-not-relaxed state. Different experiments = measure one or the other, but it is not correct to say = that they are different =E2=80=9Cmethods=E2=80=9D to describe the = ionization energy; they are different physical quantities, no more the = same than the Gibbs energy is the same as a spin-orbit correction.

On Jan 7, 2020, at 11:19 AM, Igors Mihailovs igorsm,cfi.lu.lv = <owner-chemistry!^!ccl.net> wrote:

=20 =20
Dear Dr. Molt,

I was somewhat sure that "adiabatic" ionization correspond to the relaxed geometries. You probably intended to compare "vertical" and "adiabatic" (or "relaxed-geometry"). Or am I wrong? As far as I know the term "adiabatic" is because there is no further energy exchange with the environment expected because the geometry has already been relaxed.

I also would like to add my bit to the discussion with the following points.

Adiabatic ionization energies and electron affinities are the quantities needed to compare with experimental electrochemistry, for example (see the Marcus equation), because the adiabatic difference is the driving force, but the reorganization energies (difference between the adiabatic and vertical quantities) are also involved because the transition is vibrationally-assisted.

Also, unoccupied levels for the pure (non-hybrid) Kohn=E2=80=94Sham = roughly correspond to excitation energies rather than to electron affinities (see, e.g., Baerends, E. J.; Gritsenko, O. V; van Meer, R. Phys. Chem. Chem. Phys. 2013, 15 (39), 16408). This is lost when HF admixture is introduced (as in hybrid functionals).

Also, I presume that optimally tuned range-separated hybrids are a more or less viable alternative for the costly methods because, even if they are tuned for every particular molecule, said generalized Koopmans' theorem is the basis for tuning. I cannot find the article right now, though, so I am not totally sure. For TD-DFT though, they are very good (https://pubs.acs.o= rg/doi/abs/10.1021/ct5000617).

With hope this is not rubbish,
Igors Mihailovs

On 1/7/20 2:45 PM, Robert Molt r.molt.chemical.physics{:}gmail.com wrote:
1.) Dr. Lehtola=E2=80=99s suggestion is correct. A distinction = should be made when saying that =E2=80=9CKoopmans=E2=80=99s theorem does not = hold for DFT.=E2=80=9D Whether or not =E2=80=9Cthe true=E2=80=9D DFT should have = Koopmans=E2=80=99s theorem is a subject of some scholarly debate. Dr. Bartlett=E2=80=99s work is = intended to be proof that a well-formulated DFT, with emphasis on enforcing physical constraints, can do this. This is meant to be in contrast to the zoo of highly parameterized KS-DFT functionals, which do badly poorly outside their parameterization range (the Minnesota functionals being an example which are stupendous at many, many things, then bizarrely terrible in certain circumstances outside the standard comp chem goals).

2.) None of this is intended to argue that Dr. Bartlett=E2=80=99s work is or is not the best you can do, = accuracy -wise, right here right now. 

3.) The original question has a false dichotomy. = The original question compared adiabatic vs. relaxed excitations (re-optimizing the structure of the cation or not) asking which was =E2=80=9Cmore accurate.=E2=80=9D This is wrong; my emphasis is intended for clarity, not to be pejorative. These correspond to two totally different experimental situations. If you are trying to model ionization energies, you should re-optimize the geometries iff you are comparing to experimental ionization energies where the system=E2=80=99s molecular geometry does have = time to relax. The same is true that an adiabatic ionization energy must be compared to an adiabatic ionization experiment. Usually, people mean the adiabatic ionization energy if they do not qualify what they mean (but one should specify). It would be inconsistent to use relaxed structures to compute adiabatic ionization energies.

One could argue to do this anyway, on the grounds = of judicious cancellation of error; I am ignorant, personally, of how errors cancel, assuming a systematic error exists in the first place. However, in so much as the goal of our field is to compute the right answer for the right reasons, it is inconsistent.

On Jan 7, 2020, at 4:08 AM, Susi Lehtola susi.lehtola[*]helsinki.fi <owner-chemistry/a\ccl.net> wrote:


Sent to CCL by: Susi Lehtola [susi.lehtola a helsinki.fi]
On 1/7/20 12:26 AM, Daniel Glossman-Mitnik dglossman _ = gmail.com wrote:
The Koopmans' = theorem (note that it is Koopmans, not Koopman) does not (theoretically) hold within DFT and it has been always used as approximation. However, there is another theorem that it is valid within Generalized Kohn-Sham model (GKS) that validates the use of E(HOMO as -I. This does not hold for A and the LUMO, but it can be said that A is equal to -E(HOMO) of the anion. =46rom = a practical point of view, if the E(HOMO) of the anion is equal to the E(LUMO) of the neutral, then this counterpart of Koopmans' theorem will hold within DFT. Indeed this is an approximation, and its accuracy will be depending on the model chemistry chosen for your calculations. In our research group, we have been doing investigations to find the best model chemistry that satisfies this approximation and our published results show that the MN12SX/Def2TZVP/H20 reproduce the values with great accuracy. Of course, there could be another combinations that could help (including tuned density functionals to get the desired Koopmans behavior) but most of the usually recommended density functionals are not useful in this regard.

Bartlett's "consistent DFT" should also be mentioned in this context; their QTP functionals are obtained by enforcing correct excitation spectra. See dois 10.1016/j.cplett.2016.12.017 and 10.1063/1.5116338.
--
------------------------------------------------------------------
Mr. Susi Lehtola, PhD =             Ju= nior Fellow, Adjunct Professor
susi.lehtola() alumni.helsinki.fi   University of Helsinki
http://susilehtola.github.io/     Finland
------------------------------------------------------------------
Susi Lehtola, dosentti, FT =        tutkijatohtori
susi.lehtola() alumni.helsinki.fi   Helsingin yliopisto
http://susilehtola.github.io/
------------------------------------------------------------------





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--=20
Ar cie=C5=86u,
Igors Mihailovs
Zin=C4=81tniskais asistents
Organisko materi=C4=81lu laboratorija
LU Cietvielu fizikas instit=C5=ABts
Yours faithfully,
Igors Mihailovs
Research assistant
Laboratory of Organic Materials
Institute of Solid State Physics, University of Latvia

= --Apple-Mail=_E23009D1-BC6E-4EFE-92A5-6F3EFA3516FD-- From owner-chemistry@ccl.net Wed Jan 8 10:04:00 2020 From: "Edward Brothers chicoraed/./gmail.com" To: CCL Subject: CCL: An ACS meeting in Qatar! Message-Id: <-53933-200108020300-10319-fcdJAWnUM2vBW/2gyQEjVA#,#server.ccl.net> X-Original-From: Edward Brothers Content-Type: multipart/alternative; boundary="000000000000548622059b9b7b1b" Date: Wed, 8 Jan 2020 02:02:41 -0500 MIME-Version: 1.0 Sent to CCL by: Edward Brothers [chicoraed/./gmail.com] --000000000000548622059b9b7b1b Content-Type: text/plain; charset="UTF-8" Dear Colleagues, I would like to kindly invite you to the first American Chemical Society event in the Middle East and North Africa. 'ACS Research Conference: Chemistry and Chemical Engineering in MENA' will be held on March 10-12 2020 and it will feature Nobel Laureate Sir Fraser Stoddart as a plenary speaker. The ACS president for 2020 Dr. Luis Echegoyen will be also attending (please check www.acs.qa for more details). I am especially excited to invite your computational and theoretical contributions to the session I am chairing entitled,'According to my calculations... Computational and Theoretical Results.' Lee Woodcock and Tom Miller will be at this session, as well as many local workers in computational chemistry. I am very excited for you to see what we are doing in Qatar, so please submit your work! The event will be at the Ritz Carlton Doha. There is no registration fee. If you have any questions, hit me up at ed.brothers at Qatar dot TAMU period EDU. Best regards, Edward N. Brothers Professor of Chemistry Qatar ACS Meeting Organizing Committee (Member) Texas A&M University at Qatar --000000000000548622059b9b7b1b Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

Dear C= olleagues,

=C2=A0

I would like to kindly invite you to the= first American Chemical Society event in the Middle East and North Africa.=C2=A0 'ACS = Research Conference: Chemistry and Chemical Engineering in MENA'=C2=A0 will be h= eld=C2=A0on March 10-12 2020=C2=A0and it will feature Nobel Laureate Sir Fraser Stoddart as = a plenary speaker. The ACS president for 2020 Dr. Luis Echegoyen will be also attendi= ng (please check www.acs.qa for more details).

=C2=A0

I am especially excited to invite your c= omputational and theoretical contributions to the session I am chairing entitled,'Accord= ing to my calculations...=C2=A0 Computational and Theoretical Results.'=C2=A0 Lee= Woodcock and Tom Miller will be at this session, as well as many local wor= kers in computational chemistry.=C2=A0 =C2=A0I am very excited for you to see what we are doing in Qatar, so please submit your work!

=C2=A0

The event will be at the Ritz Carlton Do= ha.=C2=A0 There is no registration fee.=C2=A0 If you have any questions, hi= t me up at ed.brothers at Qatar dot TAMU period EDU.

=C2=A0

Best regards,

=C2=A0

Edward N. Brothers

Professor of Chemistry

Qatar ACS Meeting Organizing Committee (= Member)

Texas A&M University at Qatar=C2=A0<= /font>

--000000000000548622059b9b7b1b-- From owner-chemistry@ccl.net Wed Jan 8 10:39:00 2020 From: "Margraf, Johannes johannes.margraf%ch.tum.de" To: CCL Subject: CCL: The best method to calculate the ionization potential of organic mol. Message-Id: <-53934-200108033233-25470-l4w6aaFAp410E+/K8aEAQw---server.ccl.net> X-Original-From: "Margraf, Johannes" Content-Language: en-US Content-Type: multipart/alternative; boundary="_000_71b9b40ca3c64d669fba7afb78a6a96cchtumde_" Date: Wed, 8 Jan 2020 08:32:13 +0000 MIME-Version: 1.0 Sent to CCL by: "Margraf, Johannes" [johannes.margraf]![ch.tum.de] --_000_71b9b40ca3c64d669fba7afb78a6a96cchtumde_ Content-Type: text/plain; charset="windows-1257" Content-Transfer-Encoding: quoted-printable Dear Robert, "adiabatic" does indeed mean many things in many fields, and the double-neg= ative "non-adaiabatic" adds to the confusion about this term. But, as Igors= wrote, in the context of ionization potentials (and excitation energies), = I've only ever seen the use of "vertical" and "adiabatic" to mean "fixed-ge= ometry" and "relaxed-geometry", respectively. This is also the meaning of t= hese terms in the NIST webbook and other databases. Best regards, Hannes ________________________________ > From: owner-chemistry+johannes.margraf=3D=3Dtum.de.---.ccl.net on behalf of Robert Molt r.molt.chem= ical.physics{}gmail.com Sent: Tuesday, January 7, 2020 8:30:48 PM To: Margraf, Johannes Subject: CCL: The best method to calculate the ionization potential of orga= nic mol. I am perhaps confused on the convention of =93adiabatic.=94 A smart man onc= e advised me to never use the term, since its meaning can be ambiguous ;) I= think I am using the term properly, but conventions are useful only in so = much as they make things clearer rather than less clear. Regardless, my meaning is as I wrote in the paragraph or as Dr. Mihailovs w= rote: the geometry-relaxed ionization state corresponds to a different ioni= zation energy than the geometry-not-relaxed state. Different experiments me= asure one or the other, but it is not correct to say that they are differen= t =93methods=94 to describe the ionization energy; they are different physi= cal quantities, no more the same than the Gibbs energy is the same as a spi= n-orbit correction. On Jan 7, 2020, at 11:19 AM, Igors Mihailovs igorsm,cfi.lu.lv > wrote: Dear Dr. Molt, I was somewhat sure that "adiabatic" ionization correspond to the relaxed g= eometries. You probably intended to compare "vertical" and "adiabatic" (or = "relaxed-geometry"). Or am I wrong? As far as I know the term "adiabatic" i= s because there is no further energy exchange with the environment expected= because the geometry has already been relaxed. I also would like to add my bit to the discussion with the following points= . Adiabatic ionization energies and electron affinities are the quantities ne= eded to compare with experimental electrochemistry, for example (see the Ma= rcus equation), because the adiabatic difference is the driving force, but = the reorganization energies (difference between the adiabatic and vertical = quantities) are also involved because the transition is vibrationally-assis= ted. Also, unoccupied levels for the pure (non-hybrid) Kohn=97Sham roughly corre= spond to excitation energies rather than to electron affinities (see, e.g.,= Baerends, E. J.; Gritsenko, O. V; van Meer, R. Phys. Chem. Chem. Phys. 201= 3, 15 (39), 16408). This is lost when HF admixture is introduced (as in hyb= rid functionals). Also, I presume that optimally tuned range-separated hybrids are a more or = less viable alternative for the costly methods because, even if they are tu= ned for every particular molecule, said generalized Koopmans' theorem is th= e basis for tuning. I cannot find the article right now, though, so I am no= t totally sure. For TD-DFT though, they are very good (https://pubs.acs.org= /doi/abs/10.1021/ct5000617). With hope this is not rubbish, Igors Mihailovs On 1/7/20 2:45 PM, Robert Molt r.molt.chemical.physics{:}gmail.com wrote: 1.) Dr. Lehtola=92s suggestion is correct. A distinction should be made whe= n saying that =93Koopmans=92s theorem does not hold for DFT.=94 Whether or = not =93the true=94 DFT should have Koopmans=92s theorem is a subject of som= e scholarly debate. Dr. Bartlett=92s work is intended to be proof that a we= ll-formulated DFT, with emphasis on enforcing physical constraints, can do = this. This is meant to be in contrast to the zoo of highly parameterized KS= -DFT functionals, which do badly poorly outside their parameterization rang= e (the Minnesota functionals being an example which are stupendous at many,= many things, then bizarrely terrible in certain circumstances outside the = standard comp chem goals). 2.) None of this is intended to argue that Dr. Bartlett=92s work is or is n= ot the best you can do, accuracy -wise, right here right now. 3.) The original question has a false dichotomy. The original question comp= ared adiabatic vs. relaxed excitations (re-optimizing the structure of the = cation or not) asking which was =93more accurate.=94 This is wrong; my emph= asis is intended for clarity, not to be pejorative. These correspond to two= totally different experimental situations. If you are trying to model ioni= zation energies, you should re-optimize the geometries iff you are comparin= g to experimental ionization energies where the system=92s molecular geomet= ry does have time to relax. The same is true that an adiabatic ionization e= nergy must be compared to an adiabatic ionization experiment. Usually, peop= le mean the adiabatic ionization energy if they do not qualify what they me= an (but one should specify). It would be inconsistent to use relaxed struct= ures to compute adiabatic ionization energies. One could argue to do this anyway, on the grounds of judicious cancellation= of error; I am ignorant, personally, of how errors cancel, assuming a syst= ematic error exists in the first place. However, in so much as the goal of = our field is to compute the right answer for the right reasons, it is incon= sistent. On Jan 7, 2020, at 4:08 AM, Susi Lehtola susi.lehtola[*]helsinki.fi >= wrote: Sent to CCL by: Susi Lehtola [susi.lehtola a helsinki.fi] On 1/7/20 12:26 AM, Daniel Glossman-Mitnik dglossman _ gmail.com wrote: The Koopmans' theorem (note that it is Koopmans, not Koopman) does not (the= oretically) hold within DFT and it has been always used as approximation. H= owever, there is another theorem that it is valid within Generalized Kohn-S= ham model (GKS) that validates the use of E(HOMO as -I. This does not hold = for A and the LUMO, but it can be said that A is equal to -E(HOMO) of the a= nion. From a practical point of view, if the E(HOMO) of the anion is equal = to the E(LUMO) of the neutral, then this counterpart of Koopmans' theorem w= ill hold within DFT. Indeed this is an approximation, and its accuracy will= be depending on the model chemistry chosen for your calculations. In our r= esearch group, we have been doing investigations to find the best model che= mistry that satisfies this approximation and our published results show tha= t the MN12SX/Def2TZVP/H20 reproduce the values with great accuracy. Of cour= se, there could be another combinations that could help (including tuned de= nsity functionals to get the desired Koopmans behavior) but most of the usu= ally recommended density functionals are not useful in this regard. Bartlett's "consistent DFT" should also be mentioned in this context; their= QTP functionals are obtained by enforcing correct excitation spectra. See = dois 10.1016/j.cplett.2016.12.017 and 10.1063/1.5116338. -- ------------------------------------------------------------------ Mr. Susi Lehtola, PhD Junior Fellow, Adjunct Professor susi.lehtola() alumni.helsinki.fi University = of Helsinki http://susilehtola.github.io/ Finland ------------------------------------------------------------------ Susi Lehtola, dosentti, FT tutkijatohtori susi.lehtola() alumni.helsinki.fi Helsingin y= liopisto http://susilehtola.github.io/ ------------------------------------------------------------------ the strange characters on the top line to the /a\ sign. You can also E-mail to subscribers: CHEMISTRY/a\ccl.net or use:E-mail to administrators: CHEMISTRY-REQUEST/a\ccl.net or us= e

Dear Robert,


"adiabatic" does indeed mean many things in many fields, and t= he double-negative "non-adaiabatic" adds to the confusion about t= his term. But, as Igors wrote, in the context of ionization potentials (and= excitation energies), I've only ever seen the use of "vertical" and "adiabatic" to mean "fixed-geometr= y" and "relaxed-geometry", respectively. This is also the me= aning of these terms in the NIST webbook and other databases.


Best regards,


Hannes

From: owner-chemistry+j= ohannes.margraf=3D=3Dtum.de.---.ccl.net <owner-chemistry+johannes.margra= f=3D=3Dtum.de.---.ccl.net> on behalf of Robert Molt r.molt.chemical.physics{= }gmail.com <owner-chemistry.---.ccl.net>
Sent: Tuesday, January 7, 2020 8:30:48 PM
To: Margraf, Johannes
Subject: CCL: The best method to calculate the ionization potential = of organic mol.
 
I am perhaps confused on the convention of =93adiabatic.=94 A smart ma= n once advised me to never use the term, since its meaning can be ambiguous= ;) I think I am using the term properly, but conventions are useful only i= n so much as they make things clearer rather than less clear.

Regardless, my meaning is as I wrote in the paragraph or as= Dr. Mihailovs wrote: the geometry-relaxed ionization state corresponds to = a different ionization energy than the geometry-not-relaxed state. Differen= t experiments measure one or the other, but it is not correct to say that they are different&nbs= p;=93methods=94 to describe the ionization energy; they are different physi= cal quantities, no more the same than the Gibbs energy is the same as a spi= n-orbit correction.

On Jan 7, 2020, at 11:19 AM, Igors Mihailovs igorsm,cfi.lu.= lv <owner-chemis= try]-[ccl.net> wrote:

Dear Dr. Molt,

I was somewhat sure that "adiabatic" ionization correspond to the= relaxed geometries. You probably intended to compare "vertical" = and "adiabatic" (or "relaxed-geometry"). Or am I wrong?= As far as I know the term "adiabatic" is because there is no fur= ther energy exchange with the environment expected because the geometry has already be= en relaxed.

I also would like to add my bit to the discussion with the following points= .

Adiabatic ionization energies and electron affinities are the quantities ne= eded to compare with experimental electrochemistry, for example (see the Ma= rcus equation), because the adiabatic difference is the driving force, but = the reorganization energies (difference between the adiabatic and vertical quantities) are also involved because t= he transition is vibrationally-assisted.

Also, unoccupied levels for the pure (non-hybrid) Kohn=97Sham roughly corre= spond to excitation energies rather than to electron affinities (see, e.g.,= Baerends, E. J.; Gritsenko, O. V; van Meer, R. Phys. Chem. Chem. Phys. 201= 3, 15 (39), 16408). This is lost when HF admixture is introduced (as in hybrid functionals).

Also, I presume that optimally tuned range-separated hybrids are a more or = less viable alternative for the costly methods because, even if they are tu= ned for every particular molecule, said generalized Koopmans' theorem is th= e basis for tuning. I cannot find the article right now, though, so I am not totally sure. For TD-DFT though= , they are very good (https://pubs.acs.org/doi/abs/10.1021/= ct5000617).

With hope this is not rubbish,
Igors Mihailovs

On 1/7/20 2:45 PM, Robert Molt r.molt.chemic= al.physics{:}gmail.com wrote:
1.) Dr. Lehtola=92s suggestion is correct. A distinction should be made whe= n saying that =93Koopmans=92s theorem does not hold for DFT.=94 Whether or = not =93the true=94 DFT should have Koopmans=92s theorem is a subject of som= e scholarly debate. Dr. Bartlett=92s work is intended to be proof that a well-formulated DFT, with emphasis on enforcing physica= l constraints, can do this. This is meant to be in contrast to the zoo of h= ighly parameterized KS-DFT functionals, which do badly poorly outside their= parameterization range (the Minnesota functionals being an example which are stupendous at many, many things, th= en bizarrely terrible in certain circumstances outside the standard comp ch= em goals).

2.) None of this is intended to argue that Dr. Bartlett=92s= work is or is not the best you can do, accuracy -wise, right here right no= w. 

3.) The original question has a false dichotomy. The origin= al question compared adiabatic vs. relaxed excitations (re-optimizing the s= tructure of the cation or not) asking which was =93more accurate.=94 This i= s wrong; my emphasis is intended for clarity, not to be pej= orative. These correspond to two totally different experimental situations.= If you are trying to model ionization energies, you should re-optimize the= geometries iff you are comparing to experimental ionization energies where the system=92s molecular geometr= y does have time to relax. The same is true that an adiabatic ionization en= ergy must be compared to an adiabatic ionization experiment. Usually, peopl= e mean the adiabatic ionization energy if they do not qualify what they mean (but one should specify). It would b= e inconsistent to use relaxed structures to compute adiabatic ionization en= ergies.

One could argue to do this anyway, on the grounds of judici= ous cancellation of error; I am ignorant, personally, of how errors cancel,= assuming a systematic error exists in the first place. However, in so much= as the goal of our field is to compute the right answer for the right reasons, it is inconsistent.

On Jan 7, 2020, at 4:08 AM, Susi Lehtola susi.lehtola[*]helsinki.f= i <owner-chemistry/a\ccl.net> wrote:


Sent to CCL by: Susi Lehtola [susi.lehtola a helsinki.fi]
On 1/7/20 12:26 AM, Daniel Glossman-Mitnik dglossman _ gmail.com wrote:
The Koopmans' theorem (note that it is= Koopmans, not Koopman) does not (theoretically) hold within DFT and it has= been always used as approximation. However, there is another theorem that = it is valid within Generalized Kohn-Sham model (GKS) that validates the use of E(HOMO as -I. This does not hold for= A and the LUMO, but it can be said that A is equal to -E(HOMO) of the anio= n. From a practical point of view, if the E(HOMO) of the anion is equal to = the E(LUMO) of the neutral, then this counterpart of Koopmans' theorem will hold within DFT. Indeed this is= an approximation, and its accuracy will be depending on the model chemistr= y chosen for your calculations. In our research group, we have been doing i= nvestigations to find the best model chemistry that satisfies this approximation and our published results show= that the MN12SX/Def2TZVP/H20 reproduce the values with great accuracy. Of = course, there could be another combinations that could help (including tune= d density functionals to get the desired Koopmans behavior) but most of the usually recommended density fun= ctionals are not useful in this regard.

Bartlett's "consistent DFT" should also be mentioned in this cont= ext; their QTP functionals are obtained by enforcing correct excitation spe= ctra. See dois 10.1016/j.cplett.2016.12.017 and 10.1063/1.5116338.
--
------------------------------------------------------------------
Mr. Susi Lehtola, PhD          = ;   Junior Fellow, Adjunct Professor
susi.lehtola() alumni.helsinki.fi   University of Helsinki
http://susilehtola.github.io/     Finland
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Susi Lehtola, dosentti, FT        tutkij= atohtori
susi.lehtola() alumni.helsinki.fi   Helsingin yliopisto
http://susilehtola.github.io/
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--=20
Ar cie=F2u,
Igors Mihailovs
Zin=E2tniskais asistents
Organisko materi=E2lu laboratorija
LU Cietvielu fizikas instit=FBts
Yours faithfully,
Igors Mihailovs
Research assistant
Laboratory of Organic Materials
Institute of Solid State Physics, University of Latvia

--_000_71b9b40ca3c64d669fba7afb78a6a96cchtumde_-- From owner-chemistry@ccl.net Wed Jan 8 11:14:00 2020 From: "Bruno Cramer bruno.cramer,,gmail.com" To: CCL Subject: CCL: Question about MaxEnt Message-Id: <-53935-200108073052-16111-dy/YMzUo1WZFWld2orMTWA~~server.ccl.net> X-Original-From: Bruno Cramer Content-Type: multipart/alternative; boundary="000000000000bdc9c6059ba00f47" Date: Wed, 8 Jan 2020 09:30:33 -0300 MIME-Version: 1.0 Sent to CCL by: Bruno Cramer [bruno.cramer,+,gmail.com] --000000000000bdc9c6059ba00f47 Content-Type: text/plain; charset="UTF-8" Dear Amber users, I am looking for a MaxEnt (Maximum Entropy program) that can be used to find specific aptamers based on a target structure, and after obtaining the selected aptamers by MaxEnt the resulting output may be used in Amber-MD simulation. Thank you B.Cramer --000000000000bdc9c6059ba00f47 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Dear Amber users,
I am looking for a MaxEnt= (Maximum Entropy program) that can be used to find specific aptamers based= on a target structure, and after obtaining the selected aptamers by MaxEnt= =C2=A0 the resulting output may be used in Amber-MD simulation.
<= div>Thank you
B.Cramer
--000000000000bdc9c6059ba00f47--