Publications associées à Intersection conique

Characterizing Conical Intersections in DNA/RNA Nucleobases with Multiconfigurational Wave Functions of Varying Active Space Size

We characterize the photochemically relevant conical intersections between the lowest-lying accessible electronic excited states of the different DNA/RNA nucleobases using Cholesky decomposition-based complete active space self-consistent field (CASSCF) al ...

Amer Chemical Soc2023

High-order geometric integrators for nonadiabatic molecular quantum dynamics and their applications to explore conical intersections

Seonghoon Choi

Accurate simulations of molecular quantum dynamics are crucial for understanding numerous natural processes and experimental results. Yet, such high-accuracy simulations are challenging even for relatively simple systems where the Born-Oppenheimer approxim ...

EPFL2022

How important are the residual nonadiabatic couplings for an accurate simulation of nonadiabatic quantum dynamics in a quasidiabatic representation?

Jiri Vanicek, Seonghoon Choi

Diabatization of the molecular Hamiltonian is a standard approach to remove the singularities of nonadiabatic couplings at conical intersections of adiabatic potential energy surfaces. In general, it is impossible to eliminate the nonadiabatic couplings en ...

2021

High-order geometric integrators for representation-free Ehrenfest dynamics

Jiri Vanicek, Seonghoon Choi

Ehrenfest dynamics is a useful approximation for ab initio mixed quantum-classical molecular dynamics that can treat electronically nonadiabatic effects. Although a severe approximation to the exact solution of the molecular time-dependent Schrödinger equa ...

2021

Direct Observation of Aggregation-Induced Emission Mechanism

Anne-Clémence Corminboeuf, Antonio Prlj, Kun-Han Lin, Han Han

The mechanism of aggregation-induced emission, which overcomes the common aggregation-caused quenching problem in organic optoelectronics, is revealed by monitoring the real time structural evolution and dynamics of electronic excited state with frequency ...

Wiley-VCH Verlag GmbH2020

Which form of the molecular Hamiltonian is the most suitable for simulating the nonadiabatic quantum dynamics at a conical intersection?

Jiri Vanicek, Seonghoon Choi

Choosing an appropriate representation of the molecular Hamiltonian is one of the challenges faced by simulations of the nonadiabatic quantum dynamics around a conical intersection. The adiabatic, exact quasidiabatic, and strictly diabatic representations ...

2020

Vibrationally inelastic scattering of HCl from Ag(111)

Jan Daniel Geweke

Using molecular beam cooled samples and quantum state-selective detection, we observe v = 0 -> 1 vibrational transitions when HCl (v = 0) collides with an Ag(111) surface and derive both the incidence energy and surface temperature dependence of the transi ...

AMER INST PHYSICS2020

Efficient geometric integrators for nonadiabatic quantum dynamics. II. The diabatic representation

Jiri Vanicek, Seonghoon Choi, Julien Roulet

Exact nonadiabatic quantum evolution preserves many geometric properties of the molecular Hilbert space. In the first paper of this series ["Paper I," S. Choi and J. Vaníček, J. Chem. Phys. 150, 204112 (2019)], we presented numerical integrators of arbitra ...

2019

On-the-fly ab initio semiclassical evaluation of time-resolved electronic spectra

Jiri Vanicek, Tomislav Begusic, Julien Roulet

We present a methodology for computing vibrationally and time-resolved pump-probe spectra, which takes into account all vibrational degrees of freedom and is based on the combination of the thawed Gaussian approximation with on-the-fly ab initio evaluation ...

AMER INST PHYSICS2018

Mechanism of ultrafast non-reactive deactivation of the retinal chromophore in non-polar solvents

Goran Zgrablic

The photoisomerization of the all-trans protonated Schiff base of retinal (SBR+) in solution is highly inefficient. The present theoretical and experimental investigation aims at disclosing the mechanisms of ultrafast, non-reactive relaxation of SBR+ that ...

Royal Soc Chemistry2017

Nonadiabatic effects in electronic and nuclear dynamics

Majed Chergui, Ursula Röthlisberger, Jiri Vanicek, Martin Peter Bircher, Tomas Zimmermann, Elisa Liberatore, Aurélien Kevin Fabrice Patoz, Nicholas John Browning

Due to their very nature, ultrafast phenomena are often accompanied by the occurrence of nonadiabatic effects. From a theoretical perspective, the treatment of nonadiabatic processes makes it necessary to go beyond the (quasi) static picture provided by th ...

2017

Charge Transport in Organic Nanofibrils: Lessons from Modelling

Anne-Clémence Corminboeuf, Antonio Prlj, Ganna Gryn'ova, Adrien Georges Nicolai, Pauline Jeanne Ollitrault

H-aggregates featuring tight π-stacks of the conjugated heterocyclic cores represent ideal morphologies for 1D organic semiconductors. Such nanofibrils have larger electronic couplings between the adjacent cores compared to the herringbone crystal or amorp ...

Royal Society of Chemistry2017

Beyond structure: ultrafast X-ray absorption spectroscopy as a probe of non-adiabatic wavepacket dynamics

Majed Chergui, Simon Neville

The excited state non-adiabatic dynamics of polyatomic molecules, leading to the coupling of structural and electronic dynamics, is a fundamentally important yet challenging problem for both experiment and theory. Ongoing developments in ultrafast extreme ...

Royal Soc Chemistry2016

Ultrafast Relaxation Dynamics of the Ethylene Cation C

Ursula Röthlisberger, Pablo Lopez Tarifa, Elisa Liberatore, Lamia Kasmi

We present a combined experimental and computational study of the relaxation dynamics of the ethylene cation. In the experiment, we apply an extreme-ultraviolet-pump/infrared-probe scheme that permits us to resolve time scales on the order of 10 fs. The ph ...

2016

Robust metastable skyrmions and their triangular-square lattice structural transition in a high-temperature chiral magnet

Henrik Moodysson Rønnow, Jonathan White

Skyrmions, topologically protected nanometric spin vortices, are being investigated extensively in various magnets(1-11). Among them, many structurally chiral cubic magnets host the triangular-lattice skyrmion crystal (SkX) as the thermodynamic equilibrium ...

Nature Publishing Group2016

Magnetoelectric effects in the skyrmion host material Cu2OSeO3

Helmuth Berger

Insulating helimagnetic Cu2OSeO3 shows sizeable magnetoelectric effects in its skyrmion phase. Using magnetization measurements, magneto-current analysis and dielectric spectroscopy, we provide a thorough investigation of magnetoelectric coupling, polariza ...

Nature Publishing Group2015

A Vibronic Coupling Hamiltonian to Describe the Ultrafast Excited State Dynamics of a Cu(I)-Phenanthroline Complex

Ursula Röthlisberger, Ivano Tavernelli, Thomas James Penfold, Gloria Capano

We present a model Hamiltonian to study the nonadiabatic dynamics of photoexcited Cu(dmp)(2), (dmp = 2,9-dimethyl-1,10-phenanthroline). The relevant normal modes, identified by the magnitude of the first order coupling constants, correspond closely to ...

2014

Dissipation processes in the insulating skyrmion compound Cu2OSeO3

Helmuth Berger, Ivica Zivkovic

We present a detailed study of the phase diagram surrounding the skyrmion lattice (SkL) phase of Cu2OSe2O3 using high-precision magnetic ac susceptibility measurements. An extensive investigation of transition dynamics around the SkL phase using the imagin ...

Amer Physical Soc2014

Communication: Double-hybrid functionals from adiabatic-connection: The QIDH model

Eric Albert Georges Bremond

A new approach stemming from the adiabatic-connection (AC) formalism is proposed to derive parameter-free double-hybrid (DH) exchange-correlation functionals. It is based on a quadratic form that models the integrand of the coupling parameter, whose compon ...

Amer Inst Physics2014

Measuring nonadiabaticity of molecular quantum dynamics with quantum fidelity and with its efficient semiclassical approximation

Jiri Vanicek, Tomas Zimmermann

We propose to measure nonadiabaticity of molecular quantum dynamics rigorously with the quantum fidelity between the Born-Oppenheimer and fully nonadiabatic dynamics. It is shown that this measure of nonadiabaticity applies in situations where other criter ...

American Institute of Physics2012