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Jiri Vanicek

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Publications associées (76)

Finite-Temperature, Anharmonicity, and Duschinsky Effects on the Two-Dimensional Electronic Spectra from Ab Initio Thermo-Field Gaussian Wavepacket Dynamics

Jiri Vanicek, Tomislav Begusic

Accurate description of finite-temperature vibrational dynamics is indispensable in the computation of two-dimensional electronic spectra. Such simulations are often based on the density matrix evolution, statistical averaging of initial vibrational states ...

2021

Ab initio semiclassical evaluation of vibrationally resolved electronic spectra with thawed Gaussians

Jiri Vanicek, Tomislav Begusic

Vibrationally resolved electronic spectra of polyatomic molecules provide valuable information about the quantum properties of both electrons and nuclei. This chapter reviews the recent progress in ab initio semiclassical calculations of such spectra, base ...

Elsevier2021

On-the-Fly ab initio Semiclassical Evaluation of Electronic Coherences in Polyatomic Molecules Reveals a Simple Mechanism of Decoherence

Jiri Vanicek, Nikolay Golubev, Tomislav Begusic

Irradiation of a molecular system by an intense laser field can trigger dynamics of both electronic and nuclear subsystems. The lighter electrons usually move on much faster, attosecond timescale but the slow nuclear rearrangement damps ultrafast electroni ...

2020

Semiclassical Approach to Photophysics Beyond Kasha’s Rule and Vibronic Spectroscopy Beyond the Condon Approximation. The Case of Azulene

Jacques-Edouard Moser, Marius Wehrle, Jiri Vanicek, Tomas Zimmermann, Julien Roulet, Antonio Prlj, Tomislav Begusic, Seonghoon Choi, Zhan Tong Zhang, George Cameron Fish

Azulene is a prototypical molecule with ananomalousfluorescence from the second excited electronic state,thus violating Kasha’s rule, and with an emission spectrum thatcannot be understood within the Condon approximation. To betterunderstand the photophysi ...

2020

On-the-fly ab initio semiclassical evaluation of vibronic spectra at finite temperature

Jiri Vanicek, Tomislav Begusic

To compute and analyze vibrationally resolved electronic spectra at zero temperature, we have recently implemented the on-the-fly ab initio extended thawed Gaussian approximation [A. Patoz et al., J. Phys. Chem. Lett. 9, 2367 (2018)], which accounts for an ...

2020

On-the-fly ab initio semiclassical evaluation of third-order response functions for two-dimensional electronic spectroscopy

Jiri Vanicek, Tomislav Begusic

Ab initio computation of two-dimensional electronic spectra is an expanding field, whose goal is improving upon simple, few-dimensional models often employed to explain experiments. Here, we propose an accurate and computationally affordable approach, base ...

2020

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

Semiclassical analysis of the quantum instanton approximation

Jiri Vanicek, Christophe Louis Joseph Jean-Luc Vaillant

We explore the relation between the quantum and semiclassical instanton approximations for the reaction rate constant. From the quantum instanton expression, we analyze the contributions to the rate constant in terms of minimum-action paths and find that t ...

2019

A combined on-the-fly/interpolation procedure for evaluating energy values needed in molecular simulations

Jiri Vanicek, Konstantin Karandashev

We propose an algorithm for molecular dynamics or Monte Carlo simulations that uses an interpolation procedure to estimate potential energy values from energies and gradients evaluated previously at points of a simplicial mesh. We chose an interpolation pr ...

2019

Single-Hessian thawed Gaussian approximation

Jiri Vanicek, Manuel Cordova, Tomislav Begusic

2019

Accelerating equilibrium isotope effect calculations. II. Stochastic implementation of direct estimators

Jiri Vanicek, Konstantin Karandashev

2019

A time-reversible integrator for the time-dependent Schrödinger equation on an adaptive grid

Jiri Vanicek, Seonghoon Choi

One of the most accurate methods for solving the time-dependent Schrödinger equation uses a combination of the dynamic Fourier method with the split-operator algorithm on a tensor-product grid. To reduce the number of required grid points, we let the grid ...

2019

Semiclassical analysis of the quantum instanton approximation (vol 151, 144111, 2019)

Jiri Vanicek, Christophe Louis Joseph Jean-Luc Vaillant

AMER INST PHYSICS2019

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

Jiri Vanicek, Julien Roulet, Seonghoon Choi

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

Efficient geometric integrators for nonadiabatic quantum dynamics. I. The adiabatic representation

Jiri Vanicek, Seonghoon Choi

Geometric integrators of the Schrödinger equation conserve exactly many invariants of the exact solution. Among these integrators, the split-operator algorithm is explicit and easy to implement but, unfortunately, is restricted to systems whose Hamiltonian ...

2019

On-the-Fly Ab Initio Semiclassical Evaluation of Absorption Spectra of Polyatomic Molecules beyond the Condon Approximation

Jiri Vanicek, Aurélien Kevin Fabrice Patoz, Tomislav Begusic

To evaluate vibronic spectra beyond the Condon approximation, we extend the on-the-fly ab initio thawed Gaussian approximation by considering the Herzberg–Teller contribution due to the dependence of the electronic transition dipole moment on nuclear coord ...

2018

On-the-fly ab initio three thawed Gaussians approximation: a semiclassical approach to Herzberg-Teller spectra

Jiri Vanicek, Aurélien Kevin Fabrice Patoz, Miroslav Sulc, Tomislav Begusic

2018

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

Jiri Vanicek, Julien Roulet, Tomislav Begusic

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

Nonadiabatic effects in electronic and nuclear dynamics

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

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

Accelerating equilibrium isotope effect calculations. I. Stochastic thermodynamic integration with respect to mass

Jiri Vanicek, Konstantin Karandashev

Accurate path integral Monte Carlo or molecular dynamics calculations of isotope effects have until recently been expensive because of the necessity to reduce three types of errors present in such calculations: statistical errors due to sampling, path inte ...

American Institute of Physics2017

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