Publications de Tomas Zimmermann

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

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

Role of sampling in evaluating classical time autocorrelation functions

Jiri Vanicek, Tomas Zimmermann

We analyze how the choice of the sampling weight affects efficiency of the Monte Carlo evaluation of classical time autocorrelation functions. Assuming uncorrelated sampling or sampling with constant correlation length, we propose a sampling weight for whi ...

American Institute of Physics2013

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

Evaluation of the importance of spin-orbit couplings in the nonadiabatic quantum dynamics with quantum fidelity and with its efficient “on-the-fly” ab initio semiclassical approximation

Jiri Vanicek, Tomas Zimmermann

We propose to measure the importance of spin-orbit couplings (SOCs) in the nonadiabatic molecular quantum dynamics rigorously with quantum ﬁdelity. To make the criterion practical, quantum ﬁdelity is estimated efﬁciently with the multiple-surface dephasing ...

American Institute of Physics2012

Efficient sampling avoids the exponential wall in classical simulations of fidelity

Jiri Vanicek, Cesare Mollica, Tomas Zimmermann

We analyze the efficiency of available algorithms for the simulation of classical fidelity and show that their computational costs increase exponentially with the number of degrees of freedom. Then we present an algorithm for which the number of trajectori ...

American Physical Society2011

Three applications of path integrals: equilibrium and kinetic isotope effects, and the temperature dependence of the rate constant of the [1,5] sigmatropic hydrogen shift in (Z)-1,3-pentadiene

Jiri Vanicek, Tomas Zimmermann

Recent experiments have confirmed the importance of nuclear quantum effects even in large biomolecules at physiological temperature. Here we describe how the path integral formalism can be used to describe rigorously the nuclear quantum effects on equilibr ...

Springer Verlag2010

Communications: Evaluation of the nondiabaticity of quantum molecular dynamics with the dephasing representation of quantum fidelity

Jiri Vanicek, Tomas Zimmermann

We propose an approximate method for evaluating the importance of non-Born–Oppenheimer effects on the quantum dynamics of nuclei. The method uses a generalization of the dephasing representation (DR) of quantum fidelity to several diabatic potential energy ...

American Institute of Physics2010

Efficient evaluation of the accuracy of molecular quantum dynamics on an approximate analytical or interpolated ab initio potential energy surface

Julien Ruppen, Jiri Vanicek, Tomas Zimmermann

Ab initio electronic structure methods have reached a satisfactory accuracy for the calculation of static properties, but remain too expensive for quantum dynamical calculations. Recently, an efficient semiclassical method was proposed to evaluate the accu ...

Wiley-Blackwell2010

Path integral evaluation of equilibrium isotope effects (vol 131, 024111, 2009)

Jiri Vanicek, Tomas Zimmermann

2009

Path integral evaluation of equilibrium isotope effects

Jiri Vanicek, Tomas Zimmermann

A general and rigorous methodology to compute the quantum equilibrium isotope effect is described. Unlike standard approaches, ours does not assume separability of rotational and vibrational motions and does not make the harmonic approximation for vibratio ...

2009