English
norskBlar i forfatter "Di Remigio, Roberto"
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Dalton Project: A Python platform for molecular- and electronic-structure simulations of complex systems
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-05)The <i>Dalton Project</i> provides a uniform platform access to the underlying full-fledged quantum chemistry codes Dalton and LSDalton as well as the PyFraME package for automatized fragmentation and parameterization of complex molecular environments. The platform is written in Python and defines a means for library communication and interaction. Intermediate data such as integrals are exposed to ... -
Diagrammatic Coupled Cluster Monte Carlo
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-09)We propose a modified coupled cluster Monte Carlo algorithm that stochastically samples connected terms within the truncated Baker–Campbell–Hausdorff expansion of the similarity-transformed Hamiltonian by construction of coupled cluster diagrams on the fly. Our new approach—diagCCMC—allows propagation to be performed using only the connected components of the similarity-transformed Hamiltonian, ... -
The DIRAC code for relativistic molecular calculations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-26)DIRAC is a freely distributed general-purpose program system for one-, two-, and four-component relativistic molecular calculations at the level of Hartree–Fock, Kohn–Sham (including range-separated theory), multiconfigurational self-consistent-field, multireference configuration interaction, electron propagator, and various flavors of coupled cluster theory. At the self-consistent-field level, a ... -
Four-Component Relativistic Calculations in Solution with the Polarizable Continuum Model of Solvation: Theory, Implementation and Application to the Group 16 Dihydrides H2X (X= O, S, Se, Te, Po)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014-11-20) -
Four-component relativistic density functional theory with the polarisable continuum model: application to EPR parameters and paramagnetic NMR shifts
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-01-01)The description of chemical phenomena in solution is as challenging as it is im- portant for the accurate calculation of molecular properties. Here, we present the implementation of the polarizable continuum model (PCM) in the four-component Dirac–Kohn–Sham density functional theory framework, o ↵ ering a cost-e ↵ ective way to concurrently model solvent and relativistic e ↵ ects. The ... -
Fully Polarizable QM/Fluctuating Charge Approach to Two-Photon Absorption of Aqueous Solutions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-05)We present the extension of the quantum/classical polarizable fluctuating charge model to the calculation of single residues of quadratic response functions, as required for the computational modeling of two-photon absorption cross sections. By virtue of a variational formulation of the quantum/classical polarizable coupling, we are able to exploit an atomic orbital-based quasienergy formalism to ... -
Open-ended formulation of self-consistent field response theory with the polarizable continuum model for solvation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-15)The study of high-order absorption properties of molecules is a field of growing importance. Quantumchemical studies can help design chromophores with desirable characteristics. Given that most experiments are performed in solution, it is important to devise a cost-effective strategy to include solvation effects in quantum-chemical studies of these properties. We here present an open-ended ... -
PCMSolver: an Open-Source Library for Solvation Modeling
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-25)PCMSolver is an open‐source library for continuum electrostatic solvation. It can be combined with any quantum chemistry code and requires a minimal interface with the host program, greatly reducing programming effort. As input, PCMSolver needs only the molecular geometry to generate the cavity and the expectation value of the molecular electrostatic potential on the cavity surface. It then returns ... -
A polarizable continuum model for molecules at spherical diffuse interfaces
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-03-22)We present an extension of the Polarizable Continuum Model (PCM) to simulate solvent effects at diffuse interfaces with spherical symmetry, such as nanodroplets and micelles. We derive the form of the Green’s function for a spatially varying dielectric permittivity with spherical symmetry and exploit the integral equation formalism of the PCM for general dielectric environments to recast the solvation ... -
The Polarizable Continuum Model Goes Viral! Extensible, Modular and Sustainable Development of Quantum Mechanical Continuum Solvation Models
(Doctoral thesis; Doktorgradsavhandling, 2017-01-16)Synergistic theoretical and experimental approaches to challenging chemical problems have become more and more widespread, due to the availability of efficient and accurate ab initio quantum chemical models. Limitations to such an approach do, however, still exist. The vast majority of chemical phenomena happens in complex environments, where the molecule of interest can interact with a large number ... -
Wavelet formulation of the polarizable continuum model. II. Use of piecewise bilinear boundary elements
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-07-27)The simplicity of dielectric continuum models has made them a standard tool in almost any Quantum Chemistry (QC) package. Despite being intuitive from a physical point of view, the actual electrostatic problem at the cavity boundary is challenging: the underlying boundary integral equations depend on singular, long-range operators. The parametrization of the cavity boundary should be molecular- ...
