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Related papers: Capturing anharmonic effects in single vibronic le…

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Hagedorn wavepackets have been used to compute single vibronic level (SVL) spectra efficiently in model harmonic potentials. To make the Hagedorn approach practical for realistic polyatomic molecules with anharmonicity, here we combine…

Chemical Physics · Physics 2025-01-09 Zhan Tong Zhang , Máté Visegrádi , Jiří J. L. Vaníček

We present a practical, ab initio time-dependent method using Hagedorn wavepackets to efficiently simulate single vibronic level (SVL) fluorescence spectra of polyatomic molecules from arbitrary initial vibrational levels. We apply the…

Chemical Physics · Physics 2025-10-20 Zhan Tong Zhang , Jiří J. L. Vaníček

In single vibronic level (SVL) fluorescence experiments, the electronically excited initial state is also excited in one or several vibrational modes. Whereas computing all contributing Franck-Condon factors individually becomes impractical…

Chemical Physics · Physics 2024-12-17 Zhan Tong Zhang , Jiří J. L. Vaníček

We present a simple and efficient method to incorporate anharmonic effects in the vibrational \textcolor{black}{analyses} of molecules within density functional theory (DFT) calculations. This approach is closely related to the traditional…

Single-Hessian Gaussian wavepacket dynamics (GWD) significantly reduces the computational burden of Heller's local harmonic GWD, while maintaining comparable accuracy in approximating vibronic spectra. Here, we provide a new, symplectic…

Chemical Physics · Physics 2026-05-11 Davide Barbiero , Jiří J. L. Vaníček

Simulating vibrationally resolved electronic spectra of anharmonic systems, especially those involving double-well potential energy surfaces, often requires expensive quantum dynamics methods. Here, we explore the applicability and…

Chemical Physics · Physics 2022-05-12 Tomislav Begušić , Enrico Tapavicza , Jiří Vaníček

We combine the semiclassical Herman--Kluk approximation with the coherence thermofield dynamics in order to evaluate vibrationally resolved electronic spectra at nonzero temperatures. In coherence thermofield dynamics, the dipole time…

Chemical Physics · Physics 2025-07-30 Fabian Kröninger , Caroline Lasser , Jiří J. L. Vaníček

We describe a new approach based on semiclassical molecular dynamics that allows to simulate infrared absorption or emission spectra of molecular systems with inclusion of anharmonic intensities. This is achieved from semiclassical power…

Chemical Physics · Physics 2018-11-12 Marco Micciarelli , Riccardo Conte , Jaime Suarez , Michele Ceotto

We have developed a formulation of density functional perturbation theory for the calculation of vibrational frequencies in molecules and solids, which uses numerical atomic orbitals as a basis set for the electronic states. The (harmonic)…

Materials Science · Physics 2007-05-23 J. M. Pruneda , S. K. Estreicher , J. Junquera , J. Ferrer , P. Ordejon

Hagedorn functions are carefully constructed generalizations of Hermite functions to the setting of many-dimensional squeezed and coupled harmonic systems. Wavepackets formed by superpositions of Hagedorn functions have been successfully…

Quantum Physics · Physics 2025-08-18 Jiří J. L. Vaníček , Zhan Tong Zhang

Current simulations of ultraviolet-visible absorption lineshapes, and dynamics of condensed phase systems, largely adopt a harmonic description to model vibrations. Often, this involves a model of displaced harmonic oscillators that have…

Chemical Physics · Physics 2020-01-08 Luke D. Smith , Arend G. Dijkstra

The one-electron spectral function of the Holstein-Hubbard bipolaron in one dimension is studied using cluster perturbation theory together with the Lanczos method. In contrast to other approaches, this allows one to calculate the spectrum…

Strongly Correlated Electrons · Physics 2007-06-13 Martin Hohenadler , Markus Aichhorn , Wolfgang von der Linden

We aim to automatize the identification of collective variables to simplify and speed up enhanced sampling simulations of conformational dynamics in biomolecules. We focus on anharmonic low-frequency vibrations that exhibit fluctuations on…

Statistical Mechanics · Physics 2025-08-01 Souvik Mondal , Michael A. Sauer , Matthias Heyden

We propose an accurate and efficient method to compute vibrational spectra of molecules, based on exact diagonalization of an algebraically calculated matrix based on powers of Morse coordinate. The present work focuses on the 1D potential…

Chemical Physics · Physics 2009-11-13 Andrea Bordoni , Nicola Manini

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…

Chemical Physics · Physics 2024-09-26 Tomislav Begušić , Jiří Vaníček

The anharmonicity of the acoustic phonon dispersion of graphene has been studied by the harmonic linear response (HLR) approach at finite temperature. This is a non-perturbative method based on the linear response of the system to applied…

Materials Science · Physics 2020-08-20 R. Ramirez , C. P. Herrero

We theoretically propose a multidimensional high-harmonic echo spectroscopy technique which utilizes strong optical fields to resolve coherent electron dynamics spanning an energy range of multiple electron Volts. Using our recently…

A novel hybrid spectral difference/embedded finite volume method is introduced in order to apply a discontinuous high-order method for large scale engineering applications involving discontinuities in the flows with complex geometries. In…

Numerical Analysis · Mathematics 2015-05-20 Jung J. Choi

High-harmonic spectroscopy of solids is a powerful tool, which provides access to both electronic structure and ultrafast electronic response of solids, from their band structure and density of states, to phase transitions, including the…

Optics · Physics 2022-08-31 Navdeep Rana , M. S. Mrudul , Daniil Kartashov , Misha Ivanov , Gopal Dixit

We find an exact analytical solution of the reduced density matrix from the Feynman-Vernon influence functional theory for a wave packet influenced by an environment containing a few discrete modes. We obtain two intrinsic energy scales…

Quantum Physics · Physics 2009-11-13 Matisse W. Y. Tu , Wei-Min Zhang
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