2 citations · 4 across the 8 of their papers we have counts for
8 papers
Spectroscopic photorelaxation signatures in pyrazine from nonadiabatic dynamics simulations with coupled cluster theory
Sara Angelico, Eirik F. Kjønstad, Yi-Ping Chang +3
Despite extensive theoretical and experimental efforts, the mechanisms underlying the ultrafast relaxation of pyrazine after photoexcitation remain challenging to disentangle. Rece…
Similarity Constrained CC2 for Efficient Coupled Cluster Nonadiabatic Dynamics
Leo Stoll, Sara Angelico, Eirik F. Kjønstad +1
Despite their high accuracy, standard coupled cluster models cannot be used for nonadiabatic molecular dynamics simulations because they yield unphysical complex excitation energie…
Determining minimum energy conical intersections by enveloping the seam: exploring ground and excited state intersections in coupled cluster theory
Sara Angelico, Eirik F. Kjønstad, Henrik Koch
Minimum energy conical intersections can be used to rationalize photochemical processes. In this Letter, we examine an algorithm to locate these structures that does not require th…
Understanding failures in electronic structure methods arising from the geometric phase effect
Eirik F. Kjønstad, Henrik Koch
The geometric phase effect arises from the dependence on the nuclear coordinates in the electronic Hamiltonian, leading to sign changes of the electronic wave functions upon traver…
Analytical evaluation of ground state gradients in quantum electrodynamics coupled cluster theory
Marcus Takvam Lexander, Sara Angelico, Eirik Fadum Kjønstad +1
Analytical gradients of potential energy surfaces play a central role in quantum chemistry, allowing for molecular geometry optimizations and molecular dynamics simulations. In str…
Unexpected hydrogen dissociation in thymine: predictions from a novel coupled cluster theory
Eirik F. Kjønstad, O. Jonathan Fajen, Alexander C. Paul +6
The fate of thymine upon excitation by ultraviolet radiation has been the subject of intense debate over the past three decades. Today, it is widely believed that its ultrafast exc…
Coupled cluster theory for nonadiabatic dynamics: nuclear gradients and nonadiabatic couplings in similarity constrained coupled cluster theory
Eirik F. Kjønstad, Sara Angelico, Henrik Koch
Coupled cluster theory is one of the most accurate electronic structure methods for predicting ground and excited state chemistry. However, the presence of numerical artifacts at e…
Resolving the notorious case of conical intersections for coupled cluster dynamics
Eirik F. Kjønstad, Henrik Koch
The motion of electrons and nuclei in photochemical events often involve conical intersections, degeneracies between electronic states. They serve as funnels for nuclear relaxation…