title: Modeling solvation effects in real-space and real-time within density functional approaches.
abstract: The Polarizable Continuum Model (PCM) can be used in conjunction with Density Functional Theory (DFT) and its time-dependent extension (TDDFT) to simulate the electronic and optical properties of molecules and nanoparticles immersed in a dielectric environment, typically liquid solvents. In this contribution, we develop a methodology to account for solvation effects in real-space (and real-time) (TD)DFT calculations. The boundary elements method is used to calculate the solvent reaction potential in terms of the apparent charges that spread over the van der Waals solute surface. In a real-space representation, this potential may exhibit a Coulomb singularity at grid points that are close to the cavity surface. We propose a simple approach to regularize such singularity by using a set of spherical Gaussian functions to distribute the apparent charges. We have implemented the proposed method in the Octopus code and present results for the solvation free energies and solvatochromic shifts for a representative set of organic molecules in water.
authors.affiliation: Istituto Nanoscienze - CNR, Centro S3, via Campi 213/A, 41125 Modena, Italy.
authors.forename: Alain
authors.initials: A
authors.lastname: Delgado
authors.affiliation: Istituto Nanoscienze - CNR, Centro S3, via Campi 213/A, 41125 Modena, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Corni
authors.affiliation: Istituto Nanoscienze - CNR, Centro S3, via Campi 213/A, 41125 Modena, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Pittalis
authors.affiliation: Istituto Nanoscienze - CNR, Centro S3, via Campi 213/A, 41125 Modena, Italy.
authors.forename: Carlo Andrea
authors.initials: CA
authors.lastname: Rozzi