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 -- Senior Postdoctoral Researcher École Polytechnique Fédérale de Lausanne (EPFL) and Università della Svizzera Italiana (USI) of Lugano USI Campus, Via G. Buffi 17, 6904 Lugano, Switzerland Emails: oliviero.andreussi @ epfl.ch -or- usi.ch Tel: +41-(0)58-666-4810 / Skype: olivieroandreussi Web: https://sites.google.com/site/olivieroandreussi On 03/08/2016 12:51 PM, Giuseppe Mattioli wrote: > 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
