Dear Oliviero Thank you for your prompt and detailed answer! I will surely contact you in private for further discussions. Best Wishes Giuseppe
On Wednesday, March 09, 2016 10:49:52 AM Oliviero Andreussi wrote: > Hi Giuseppe, > > You can play with the same two parameters in Environ as well, you just > need to set env_static_permittivity (and env_optical_permittivity for > TDDFT) to the ones of the medium you want to simulate. This is assuming > that you are only interested in the electrostatic interaction with the > solvent and that the shape of the cavity, i.e. how close to the solute > you get the continuum solvent, does not depend on the kind of solvent. > Both these assumptions are implicit in your analogy with COSMO (which by > the way is a less refined continuum model than the standard PCM or than > the SCCS model of Environ), but they may be crude depending in the > system/property you want to study. In particular, I am quite sure that > standard PCM uses a different scaling of the size of the cavity for > different solvents. > > Clearly, if you are only interested in studying the effects of a > different dielectric constant of the environment on your embedded > quantum-mechanical system (e.g. as was done in Fortunelli et al. Angew. > Chem. Int. Ed. 126, 6787 (2014) doi:10.1002/ange.201403264) you can do > it very easily with the parameters above. Instead of using one of the > preset solvent setups (environ_type = > vacuum/water/water-cation/water-anion), you specify in input only the > dielectric constant that you want to use, env_static_permittivity = XXX, > and use the defaults for all the other parameters (which corresponds to > no contribution from non-electrostatic terms, env_pressure = 0.D0, > env_surface_tension = 0.D0, and to a shape of the cavity equal to the > one optimized for water, rhomax = 0.005, rhomin = 0.0001). > > Otherwise, if you have to study a well defined solvent and want to be > more accurate, you would need to redo the parametrization of the model > for the new solvent, which for Environ only requires to tune 3 (or 4) > parameters (rhomax and rhomin, which controls the shape of the cavity, > env_static_permittivity and env_pressure, which are used to model non > electrostatic effects in a simplified way). Ideally you want to tune > these parameters to reproduce experimental solvation free energies of a > reasonable range of solutes in the new solvent (a good database of > experimental data is from the group of Truhlar > http://comp.chem.umn.edu/mnsol/ ). > > Since I am trying to improve on the documentation of the module, which > probably is not clear enough, can I ask you which documentation have you > been studying? The website (www.quantum-environ.org), the input keywords > (as in the Environ/Doc/ directory or from the website > http://nebula.wsimg.com/c3d04ee804fb1a1ddb5402d80b7c8194?AccessKeyId=ECF106C2B7F0B5C40F7B&disposition=0&alloworigin=1 > ), the references? If you have more doubts on setting up the input or on > the implemented models, please don't hesitate to write to the forum or > to contact me directly. > > Regards, > > Oliviero Andreussi > > > Dear All > > I was studying the documentation of the ENVIRON 0.2 plugin and it seems > > that water only is coded as solvent for isolated molecules. I was > > wondering > > whether there is somewhere a subset of variables (which I was not able to > > found...) that setup alternative dielectric media as in the case of the > > COSMO model (cited in the ENVIRON documentation), which basically requires > > the solvent dielectric constant (ground state DFT) or dielectric > > constant+refractive index (TDDFT) only. > > Thank you in advance > > Giuseppe > > > > ******************************************************** > > - Article premier - Les hommes naissent et demeurent > > libres et égaux en droits. Les distinctions sociales > > ne peuvent être fondées que sur l'utilité commune > > - Article 2 - Le but de toute association politique > > est la conservation des droits naturels et > > imprescriptibles de l'homme. Ces droits sont la liberté, > > la propriété, la sûreté et la résistance à l'oppression. > > ******************************************************** > > > > Giuseppe Mattioli > > CNR - ISTITUTO DI STRUTTURA DELLA MATERIA > > v. Salaria Km 29,300 - C.P. 10 > > I 00015 - Monterotondo Stazione (RM), Italy > > Tel + 39 06 90672836 - Fax +39 06 90672316 > > E-mail: <[email protected]> > > http://www.ism.cnr.it/english/staff/mattiolig > > ResearcherID: F-6308-2012 > > > > _______________________________________________ > > Pw_forum mailing list > > [email protected] > > http://pwscf.org/mailman/listinfo/pw_forum > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum ******************************************************** - Article premier - Les hommes naissent et demeurent libres et égaux en droits. Les distinctions sociales ne peuvent être fondées que sur l'utilité commune - Article 2 - Le but de toute association politique est la conservation des droits naturels et imprescriptibles de l'homme. Ces droits sont la liberté, la propriété, la sûreté et la résistance à l'oppression. ******************************************************** Giuseppe Mattioli CNR - ISTITUTO DI STRUTTURA DELLA MATERIA v. Salaria Km 29,300 - C.P. 10 I 00015 - Monterotondo Stazione (RM), Italy Tel + 39 06 90672836 - Fax +39 06 90672316 E-mail: <[email protected]> http://www.ism.cnr.it/english/staff/mattiolig ResearcherID: F-6308-2012 _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
