241 citations · 752 across the 28 of their papers we have counts for
28 papers · 1 filter
Coupled Cluster Amplitude Extrapolation in Geometry Optimization
Jonas Beck, Michele Nottoli, Tommaso Nottoli +3
In this work, we present an amplitude extrapolation ansatz for geometry optimization that uses calculations from previous steps to construct an initial guess for the quasi-Newton s…
Use of Cholesky decomposition in the CFOUR program package
Jürgen Gauss, Simon Blaschke, Sophia Burger +10
An overview is given about our efforts to speed up high-level computations of molec- ular energies and properties using Cholesky decomposition (CD). We describe the cor- responding…
Critical point search and linear response theory for computing electronic excitation energies of molecular systems. Part II. CASSCF
Laura Grazioli, Yukuan Hu, Tommaso Nottoli +2
The computation of excited states within the Complete Active Space Self-Consistent Field (CASSCF) framework remains a significant challenge in quantum chemistry, both theoretically…
Experimental proof of strong - mixing in the Renner-Teller and Pseudo-Jahn-Teller affected CCH () ion
Kim Steenbakkers, P. Bryan Changala, Weslley G. D. P. Silva +8
The ethynyl radical cation, CCH (), offers a unique system for fundamental spectroscopic studies of non-adiabatic effects due to its open-shell linear structure and the pr…
Solvation Lies Within: Simulating Condensed-Phase Properties from Local Electronic Structures
Kasper F. Schaltz, Jonas Greiner, Filippo Lipparini +1
In transitions between different environmental settings, a molecular system inevitably undergoes a range of detectable changes, and the ability to accurately simulate such response…
A novel implementation of CCSD analytic gradients using Cholesky decomposition of the two-electron integrals and Abelian point-group symmetry
Luca Melega, Tommaso Nottoli, Jürgen Gauss +1
We present a novel and efficient implementation of coupled-cluster with singles and doubles (CCSD) analytic gradients that combines the Cholesky decomposition (CD) of electron-repu…
The QUEST Database of Highly-Accurate Excitation Energies
Pierre-François Loos, Martial Boggio-Pasqua, Aymeric Blondel +2
We report theoretical best estimates of vertical transition energies (VTEs) for a large number of excited states and molecules: the \textsc{quest} database. This database includes…
A polarizable CASSCF/MM approach using the interface between OpenMMPol library and CFour
Tommaso Nottoli, Mattia Bondanza, Filippo Lipparini +1
We present a polarizable embedding quantum mechanics/molecular mechanics (QM/MM) framework for ground- and excited-state Complete Active Space Self-Consistent Field (CASSCF) calcul…
Reference CC3 Excitation Energies for Organic Chromophores: Benchmarking TD-DFT, BSE/ and Wave Function Methods
Iryna Knysh, Filippo Lipparini, Aymeric Blondel +4
To expand the QUEST database of highly-accurate vertical transition energies, we consider a series of large organic chromogens ubiquitous in dye chemistry, such as anthraquinone, a…
Cholesky decomposition in spin-free Dirac-Coulomb coupled-cluster calculations
Tereza Uhlířová, Davide Cianchino, Tommaso Nottoli +2
We present an implementation for the use of Cholesky decomposition (CD) of two-electron integrals within the spin-free Dirac-Coulomb (SFDC) scheme that enables to perform high-accu…
MBE-CASSCF Approach for the Accurate Treatment of Large Active Spaces
Jonas Greiner, Ivan Gianni, Tommaso Nottoli +3
We present a novel implementation of the complete active space self-consistent field (CASSCF) method that makes use of the many-body expanded full configuration interaction (MBE-FC…
The OpenMMPol Library for Polarizable QM/MM Calculations of Properties and Dynamics
Mattia Bondanza, Tommaso Nottoli, Michele Nottoli +3
We present a new library designed to provide a simple and straightforward way to implement QM/AMOEBA and other polarizable QM/MM methods based on induced point dipoles. The library…
A novel coupled-cluster singles and doubles implementation that combines the exploitation of point-group symmetry and Cholesky decomposition of the two-electron integrals
Tommaso Nottoli, Jürgen Gauss, Filippo Lipparini
A novel implementation of the coupled-cluster singles and doubles (CCSD) approach is presented that is specifically tailored for the treatment of large, symmetric systems. It fully…
Heptazine, Cyclazine, and Related Compounds: Chemically-Accurate Estimates of the Inverted Singlet-Triplet Gap
Pierre-François Loos, Filippo Lipparini, Denis Jacquemin
Molecules that violate Hund's rule and exhibit an inverted gap between the lowest singlet and triplet excited states have attracted considerable attention due to their…
A Cholesky decomposition-based implementation of relativistic two-component coupled-cluster methods for medium-sized molecules
Chaoqun Zhang, Filippo Lipparini, Stella Stopkowicz +2
A Cholesky decomposition (CD)-based implementation of relativistic two-component coupled-cluster (CC) and equation-of-motion CC (EOM-CC) methods using an exact two-component Hamilt…
CASSCF response equations revisited: a simple and efficient iterative algorithm
Riccardo Alessandro, Ivan Giannì, Federica Pes +2
We present an algorithm to solve the CASSCF linear response equations that is both simple and efficient. The algorithm makes use of the well established symmetric and antisymmetric…
A Quasi Time-Reversible scheme based on density matrix extrapolation on the Grassmann manifold for Born-Oppenheimer Molecular Dynamics
Federica Pes, Ètienne Polack, Patrizia Mazzeo +3
This article proposes a so-called Quasi Time-Reversible (QTR G-Ext) scheme based on Grassmann extrapolation of density matrices for an accurate calculation of initial guesses in Bo…
Computation of NMR shieldings at the CASSCF level using gauge-including atomic orbitals and Cholesky decomposition
Tommaso Nottoli, Sophia Burger, Stella Stopkowicz +2
We present an implementation of coupled-perturbed complete active space self-consistent field (CP-CASSCF) theory for the computation of nuclear magnetic resonance chemical shifts u…
Cholesky decomposition of two-electron integrals in quantum-chemical calculations with perturbative or finite magnetic fields using gauge-including atomic orbitals
Jürgen Gauss, Simon Blaschke, Sophia Burger +3
A rigorous analysis is carried out concerning the use of Cholesky decomposition (CD) of two-electron integrals in the case of quantum-chemical calculations with finite or perturbat…
A Mountaineering Strategy to Excited States: Revising Reference Values with EOM-CC4
Pierre-Fran\{c}ois Loos, Filippo Lipparini, Devin A. Matthews +2
In the framework of the computational determination of highly-accurate vertical excitation energies in small organic compounds, we explore the possibilities offered by the equation…
Grassmann extrapolation of density matrices for Born-Oppenheimer molecular dynamics
Etienne Polack, Geneviève Dusson, Benjamin Stamm +1
Born-Oppenheimer Molecular Dynamics (BOMD) is a powerful but expensive technique. The main bottleneck in a density functional theory bomd calculation is the solution to the Kohn-Sh…
A black-box, general purpose quadratic self-consistent field code with and without Cholesky Decomposition of the two-electron integrals
Tommaso Nottoli, Jürgen Gauss, Filippo Lipparini
We present the implementation of a quadratically convergent Self-consistent field (QCSCF) algorithm based on an adaptive trust-radius optimization scheme for restricted open-shell…
NMR Chemical Shift Computations at Second-Order Møller-Plesset Perturbation Theory Using Gauge-Including Atomic Orbitals and Cholesky-Decomposed Two-Electron Integrals
Sophia Burger, Filippo Lipparini, Jürgen Gauss +1
We report on a formulation and implementation of a scheme to compute NMR shieldings at second-order Moller-Plesset (MP2) perturbation theory using gauge-including atomic orbitals (…
How accurate are EOM-CC4 vertical excitation energies?
Pierre-François Loos, Devin A. Matthews, Filippo Lipparini +1
We report the first investigation of the performance of EOM-CC4 -- an approximate equation-of-motion coupled-cluster model which includes iterative quadruple excitations -- for ver…