From owner-chemistry@ccl.net Thu Nov 15 21:24:01 2018 From: "tianxiaohui]~[zju.edu.cn" To: CCL Subject: CCL:G: Low-progression Franck-Condon transitions Message-Id: <-53548-181115203957-9348-kU7JQLr5FgMVa4vuafCIcA]=[server.ccl.net> X-Original-From: tianxiaohui++zju.edu.cn Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Date: Fri, 16 Nov 2018 09:39:33 +0800 (GMT+08:00) MIME-Version: 1.0 Sent to CCL by: tianxiaohui/./zju.edu.cn Dear Julien, Thank you for your previous explanations. Some of my molecules show large displacements. I'd like to know could I use AH+zmatrix in Gaussian16 now? I did z-matrix frequency calculations in Gaussian16, but the TD result is still the same with AH+cartesian and I don't know why. Thank you for your kind help. > -----原始邮件----- > 发件人: "Tobias Kraemer Tobias.Kraemer=-=mu.ie" > 发送时间: 2018-11-12 19:32:50 (星期一) > 收件人: "Tian, Xiaohui " > 抄送: > 主题: CCL:G: Low-progression Franck-Condon transitions > > > Sent to CCL by: Tobias Kraemer [Tobias.Kraemer(a)mu.ie] > Dear Julien, > > Thank you for your additional explanations and suggestions. There is plenty of things to try out now. This will take some time, > If there a further questions I will turn to you again. > > Kind regards, > > Tobias > > Dr. Tobias Krämer > Lecturer in Inorganic Chemistry > Department of Chemistry > > Maynooth University, Maynooth, Co. Kildare, Ireland. > E: tobias.kraemer-.-mu.ie   T: +353 (0)1 474 7517 > > > > > Sent to CCL by: "Julien Bloino" [julien.bloino:_:gmail.com] Dear Dr. > > Krämer, > > > > As commented by Dr. Götze, the likely reason for the small progression > > is a significant shift of one or more modes. > > The keywords are for G16 and should be inserted in the `ReadFCHT` > > section (Freq=ReadFCHT). > > You can see the shift vector with > > `Print=Matrix=K` > > Depending on the symmetry and the structural changes, you may improve > > the convergence by increasing the maximum number of quanta for the > > overtones (MaxC1) and 2-modes combinations (MaxC2): > > `Prescreening=(MaxC1=20,MaxC2=13)` (those are the default values.) > > This is rarely sufficient to fix the convergence issue and you may > > want to check the presence of low-frequency large amplitude modes > > (large shift of low-energy modes) and potentially exclude them as they > > are poorly treated with this model. > > You can do them with: > > `RedDim=Block` > > followed by the list of modes to exclude (the reference state is the > > lower state, so you will have to list the modes to exclude from the > > initial state, compatible with the definition of the shift vector K). > > Note that Gaussian will try to build a consistent set of modes (same > > number in each state) to exclude from the vibronic treatment. It has a > > safety check to stop if too many modes are selected this way compared > > to the initial list. You can force it by changing the value of > > `RedDim=BlockTol` The definition of the set of modes to exclude is > > based on the Duschinsky matrix, which can be printed with, > > `Print=Matrix=J` (we generally always print both J and K with > > `Print=Matrix=JK`) > > Be careful in the truncation as the model system obtained this way may > > not be representative of the full system anymore. > > > > To obtain a fully converged spectrum, you can use the time-dependent > > formalism instead of the sum-over-states one (the default in this > > case) with the option `TimeDependent` I would recommend to use first > > TI to setup your protocol (trying the options described above) and > > once a sufficient convergence is reached, use TD to obtain the full > > band-shape. Indeed, the breakdown of the Franck-Condon approximation > > has a direct impact on a TI calculations (low and slow convergence) > > but is difficult to detect within the TD framework (the spectrum is > > always fully converged by definition). > > > > Regarding ForcePrtSpectrum, the option (and all "advanced" options) is > > still there but I chose not to document it as it is a double-edged > > sword and could be misinterpreted. There are technically 2 separate > > checks but the one you mention will not be helpful in your case (at > > least in a first time). > > - the first test is on the overall convergence after 2-modes > > combinations. If it is below 20% (which is the case here), Gaussian > > will stop. You can override this with `Advanced=ForceFCCalc` > > - the second test is at the end of the calculations, before printing > > the spectrum. If the progression is below 50%, the spectrum is not printed. > > You can override this with > > `Advanced=ForcePrtSpectrum` > > > > Regarding the description of the potential energy surfaces, Gaussian > > supports AdiabaticHessian (AH, the default), AdiabaticShift (AS), > > VerticalHessian (VH, also noted VFC) and VerticalGradient (VG, aka LCM > > or IMDHO). From my understanding, a behavior similar to IMDHO-FA would > > be obtained in Gaussian with `VerticalHessian > > DataMod=Duschinsky=Identity` Simplified models (like VG) should be > > used with care. While it is easier to reach convergence with them, > > they can also misrepresent the actual system, leading to incorrect > > spectra. The validity of such approximation will depend on your > > system. > > > > I hope this will answer your questions regarding the progression and > > keywords. > > > > Best regards, > > > > Julien Bloino > > > > ------ Original Message ------ > > > From: "Tobias Kraemer Tobias.Kraemer!A!mu.ie" > > > > > To: "Bloino, Julien " > > Sent: 2018-10-30 03:36:55 > > Subject: CCL:G: Low-progression Franck-Condon transitions > > > > >Dear Jan, > > > > > > > > >thanks for your reply. Sorry for being so unspecific in my post, I > > >thought this was a more generic error that could be solved more easily. > > >You are right about the fact that the geometries of the ground and > > >excited state of this ZnPc complex differ (not too a large extend, > > >but obviously enough). The ground state is planar with D4h symmetry, > > >while the structure of the (1st) excited state converges to a > > >C2v-symmetric geometry (consistent with literature J. Chem. Phys., > > >2015, 142, 094310). In fact the white paper by Barone > > >"Vibrationally-excited states in Gaussian09" mentions the distortion > > >of the excited state geometry away from a planar geometry in the > > >ground state can cause problems (and FC does not apply). However, > > >since the aforementioned paper in J. Chem. Phys. presents a FC > > >spectrum, I believe that it must still be possible to generate the > > >spectrum, and find a way around this issue. I should also mention > > >that by visual inspection the excited state geometry is not hugely > > >different from the ground state (but obviously large enough to cause > > >a problem). It seems in G09 one could force the plot of a spectrum > > >nonetheless, via FORCEPRTSPECTRUM. My question was also regarding a > > >range of other keywords that might be useful here > > >(MAXBANDS/MAXC1/MAXOVR..). So the question still stands, since I think it must be possible to solve this issue. > > > > > > > > >Nonetheless, I might try one of your suggestions as well, thanks for > > >pointing me in this direction. > > > > > > > > >Best, > > > > > > > > >Tobias > > > > > > > > > > > > > > >Dr Tobias Krämer > > > > > >Lecturer in Inorganic Chemistry > > > > > >Department of Chemistry > > > > > >Maynooth University > > > > > >[Maynooth University PNG Trans] > > > > > >Maynooth University, Maynooth, Co. Kildare, Ireland. > > > > > >E: tobias.kraemer|-|mu.ie T: +353 (0)1 474 7517 > > > > > >________________________________ > > >>From: owner-chemistry+tobias.kraemer==mu.ie|-|ccl.net > > >> on behalf of Jan > > >>Götze jgoetze[]zedat.fu-berlin.de > > >Sent: Saturday, October 27, 2018 4:25:23 PM > > >To: Tobias Kraemer > > >Subject: CCL:G: Low-progression Franck-Condon transitions > > > > > > > > >Sent to CCL by: =?UTF-8?Q?Jan_G=c3=b6tze?= > > >[jgoetze##zedat.fu-berlin.de] Dear Tobias, > > > > > >the data you provided only allow for limited analysis why your proble > > >occurs. In case you did not do any errors in preparation of your two > > >excited states, it appears that the minima of ground and excited > > >state are very distant from each other (such as groups rotating, > > >and/or normal modes differing strongly between ground and excited > > >state). For a large, planar, aromatic system like pc this is rather > > >unusual. As such, without further details on the molecular structure, > > >any additional help can only be guesswork. > > > > > >To obtain a preliminary spectrum quickly and often without problems, > > >I personally would suggest using a vertical TD approach, which might > > >be available in Gaussian16, or an IMDHO-FA as in ORCA. See for > > >example doi:10.1021/ct500830a > > > > > >Cheers, > > >Jan > > > > > >Am 26.10.2018 um 12:57 schrieb Tobias Kraemer tobias.kraemer[a]mu.ie: > > >>Sent to CCL by: "Tobias Kraemer" [tobias.kraemer_._mu.ie] Hello > > >>everyone, > > >> > > >>I am interested in calculating vibrationally-resolved spectra in G16. > > >>The > > >>molecule in question is a phthalocyanine (pc) complex. I've followed > > >>the protocol detailed in the whitepaper by Barone et al., however in > > >>the final step (generating the spectrum) an error occurs: > > >> > > >> > > >> ================================================== > > >> Calculations of Band Intensities > > >> ================================================== > > >> > > >> -- To: vibronic fundamental state -- > > >> Spectrum progression: 0.06% > > >> > > >> -- To: single overtones -- > > >> Spectrum progression: 0.71% > > >> > > >> -- To: combinations of 2 simultaneously excited modes -- > > >> Spectrum progression: 4.14% > > >> > > >> ERROR: Low progression after class 2. Total convergence = 4.1%. > > >> The vibronic spectrum will likely be unreliable. Stopping. > > >> > > >>The whitepaper provides some possible causes, but I'd like to ask > > >>for some expert opinions here on CCL nonetheless. In the excited > > >>state optimisation I have included 6 states, of which the gradients > > >>for the first one are to be followed [TD=(Read,NStates=6,Root=1)]. > > >>There are a good number of keywords listed on the Gaussian16 webpage > > >>that relate to this type of calculation, and I'd appreciate some > > >>guidance on the above issue and possible ways around it. > > >> > > >>Thanks for your help, as always much appreciated. > > >> > > >>Kind regards, > > >> > > >>Tobias>