Weighted-density functionals for cavity formation and dispersion energies in continuum solvation models.
J Chem Phys
; 141(13): 134105, 2014 Oct 07.
Article
em En
| MEDLINE
| ID: mdl-25296782
ABSTRACT
Continuum solvation models enable efficient first principles calculations of chemical reactions in solution, but require extensive parametrization and fitting for each solvent and class of solute systems. Here, we examine the assumptions of continuum solvation models in detail and replace empirical terms with physical models in order to construct a minimally-empirical solvation model. Specifically, we derive solvent radii from the nonlocal dielectric response of the solvent from ab initio calculations, construct a closed-form and parameter-free weighted-density approximation for the free energy of the cavity formation, and employ a pair-potential approximation for the dispersion energy. We show that the resulting model with a single solvent-independent parameter the electron density threshold (nc), and a single solvent-dependent parameter the dispersion scale factor (s6), reproduces solvation energies of organic molecules in water, chloroform, and carbon tetrachloride with RMS errors of 1.1, 0.6 and 0.5 kcal/mol, respectively. We additionally show that fitting the solvent-dependent s6 parameter to the solvation energy of a single non-polar molecule does not substantially increase these errors. Parametrization of this model for other solvents, therefore, requires minimal effort and is possible without extensive databases of experimental solvation free energies.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Termodinâmica
/
Tetracloreto de Carbono
/
Água
/
Clorofórmio
/
Modelos Químicos
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
J Chem Phys
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Estados Unidos