Mapping Ultrafast Energy Transfer Across Electronic and Nuclear Degrees of Freedom

2020 ◽  
Author(s):  
Eric A. Arsenault ◽  
Yusuke Yoneda ◽  
Masakazu Iwai ◽  
Krishna K. Niyogi ◽  
Graham R. Fleming
Keyword(s):  
Energy Transfer ◽  
Degrees Of Freedom

Using Time-Periodicity for Inducing Energy Transfer Between Vibration Modes

2013 ◽  
Author(s):  
Fadi Dohnal ◽  
Aleš Tondl
Keyword(s):  
Energy Transfer ◽  
Degrees Of Freedom ◽  
Vibrational Energy ◽  
Low Frequency ◽  
Vibration Modes ◽  
Present Contribution ◽  
Multiple Degrees Of Freedom ◽  
Time Periodicity ◽  
The Many ◽  
And Control

Introducing time-periodicity in system parameters may lead, in general, to a dangerous and well-known parametric resonance. In contrast to such a resonance, a properly tuned time-periodicity is capable of transferring energy between vibration modes. Time-periodicity in combination with system damping is capable of efficiently extracting vibrational energy from the system and of amplifying the existing damping affecting transient vibrations. Operating the system at such a specific time-periodicity, the system is tuned at a parametric anti-resonance. The basic principle of this concept has been studied theoretically and was proven experimentally. The physical interpretation of this concept was proposed in “Damping by Parametric Stiffness Excitation: Resonance and Anti-Resonance”, Journal of Vibration and Control, 2008, for a multiple degrees of freedom system. The present contribution highlights those findings on a multiple degrees of freedom system. It is illustrated that a parametric anti-resonance is connected to inducing an energy transfer between two of the many vibration modes of the underlying system with constant coefficients. The induced energy transfer can be utilized to transfer the vibration energy from low frequency to high frequency or vice versa or, in case of system damping, to a more efficient dissipation of vibrational energy. The achievable energy dissipation is most significant if an energy transfer is induced between a lightly damped mode and a strongly damped mode.

scholarly journals Energy transfer within the hydrogen bonding network of water following resonant terahertz excitation

2020 ◽  
Vol 6 (17) ◽  
pp. eaay7074 ◽  
Author(s):  
Hossam Elgabarty ◽  
Tobias Kampfrath ◽  
Douwe Jan Bonthuis ◽  
Vasileios Balos ◽  
Naveen Kumar Kaliannan ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Energy Transfer ◽  
Intermolecular Interactions ◽  
Degrees Of Freedom ◽  
Translational Motion ◽  
Ab Initio Molecular Dynamics ◽  
Terahertz Pulses ◽  
Rotational Degrees Of Freedom ◽  
Dynamics Simulations ◽  
Pump Probe Experiment

Energy dissipation in water is very fast and more efficient than in many other liquids. This behavior is commonly attributed to the intermolecular interactions associated with hydrogen bonding. Here, we investigate the dynamic energy flow in the hydrogen bond network of liquid water by a pump-probe experiment. We resonantly excite intermolecular degrees of freedom with ultrashort single-cycle terahertz pulses and monitor its Raman response. By using ultrathin sample cell windows, a background-free bipolar signal whose tail relaxes monoexponentially is obtained. The relaxation is attributed to the molecular translational motions, using complementary experiments, force field, and ab initio molecular dynamics simulations. They reveal an initial coupling of the terahertz electric field to the molecular rotational degrees of freedom whose energy is rapidly transferred, within the excitation pulse duration, to the restricted translational motion of neighboring molecules. This rapid energy transfer may be rationalized by the strong anharmonicity of the intermolecular interactions.

Study of Targeted Energy Transfer Inside Three-Dimensional Acoustic Cavity by Two Nonlinear Membrane Absorbers and an Acoustic Mode

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Xian Wu ◽  
Jianwang Shao ◽  
Bruno Cochelin
Keyword(s):  
Energy Transfer ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Low Frequency ◽  
Nonlinear Energy Sink ◽  
Acoustic Mode ◽  
Targeted Energy Transfer ◽  
Working Zone ◽  
Acoustic Cavity ◽  
Acoustic Cavities

As a new approach to passive sound control in low-frequency domain, the targeted energy transfer (TET) phenomenon has been investigated inside a three-dimensional (3D) acoustic cavity by considering a two degrees-of-freedom (DOF) system with an acoustic mode and a membrane nonlinear energy sink (NES). The beginning of TET phenomenon of the 2DOF system and the desired working zone for the membrane NES have been defined. In order to enhance the robustness and the effective TET range in acoustic cavities, a 3DOF system with two membranes and one acoustic mode is studied in this paper. We consider two different membranes and two almost identical membranes to analyze the TET phenomenon, respectively. The desired working zone which was obtained by the 2DOF system is applied to analyze the 3DOF system. We observe that two membranes can enlarge the desired working zone.

Targeted energy transfer in a 2-DOF mechanical system coupled to a non-linear energy sink with varying stiffness

2015 ◽  
Vol 23 (16) ◽  
pp. 2567-2577 ◽  
Author(s):  
Claude-Henri Lamarque ◽  
F Thouverez ◽  
B Rozier ◽  
Z Dimitrijevic
Keyword(s):  
Energy Transfer ◽  
Mechanical System ◽  
Degrees Of Freedom ◽  
Dynamical Behavior ◽  
Practical Investigations ◽  
Targeted Energy Transfer ◽  
Constant Stiffness ◽  
Non Linear ◽  
Energy Sink ◽  
Linear Mechanical System

The dynamical behavior of a non-linear mechanical system with two degrees of freedom (DOFs) during free and forced excitations is studied analytically and numerically. The non-linearity of the system is represented intentionally by a smooth non-linear simple function with periodically varying stiffness around a constant value for the sake of practical investigations. Analysis of the system leads to a method that could be used to design the non-linear energy sink (NES) so that the behavior of the system during relaxation and its strongly modulated response (SMR) could be improved versus the constant stiffness configuration.

Weakly Bound Molecular Complexes as Model Systems for Understanding Chemical Reactions

1996 ◽  
Author(s):  
R. E. Miller
Keyword(s):  
Energy Transfer ◽  
Degrees Of Freedom ◽  
Normal Modes ◽  
Molecular Complexes ◽  
Model Systems ◽  
Bond Rupture ◽  
Detailed Characterization ◽  
Weakly Bound ◽  
Fundamental Level ◽  
Formidable Challenge

An issue of central importance in chemical reaction dynamics is the nature of the energy transfer processes within and between reactants and products. At a fundamental level, bond rupture and formation can be understood in terms of the transfer of energy into the reaction coordinate, causing a bond to break, and then relaxation of the energy away from the newly formed bonds in the product molecules to the other degrees of freedom of the system. By their very nature, these processes are highly anharmonic, making their detailed characterization a formidable challenge. In recent years, spectroscopists have taken on the challenge of trying to characterize the quantum states of a molecule at the high vibrational energies corresponding to the chemically interesting regime. At these energies, the density of states becomes extremely high and the coupling between the states very strong, the result being that the vibrations can no longer be characterized in terms of simple isolated local or normal modes. In the extreme limit, where RRKM theory (Wardlaw and Marcus 1987) applies, there is rapid energy redistribution that, at least approximately, samples the available states statistically, allowing us to overlook many of the fine details. Although we are still far from having a complete understanding of the quantum state dynamics of systems in this regime, the recent progress that has been made in both experiment (Felker and Zewail, 1985; Go et al., 1990; Parameter 1982, 1983; Smalley 1982) and theory (Stuchebrukhov and Marcus 1993; Uzer 1991) is helping to better define the important processes. Ultimately, the detailed characterization of all the intramolecular couplings in a molecule would provide us with a basis for understanding the chemistry at a fundamental level, in both the statistical and nonstatistical regimes. After all, energy transfer from one vibrational mode of a molecule to another is determined by the intermode couplings, which, in the ground electronic states of molecules, are predominantly due to anharmonic and/or coriolis effects. Of course, the problem becomes even more challenging when one moves from the realm of isolated molecules to solvated systems.

Irreversible Passive Energy Transfer in the Damped Response of Coupled Oscillators With Essential Nonlinearity

2005 ◽  
Author(s):  
G. Kerschen ◽  
Y. S. Lee ◽  
A. F. Vakakis ◽  
D. M. McFarland ◽  
L. A. Bergman
Keyword(s):  
Energy Transfer ◽  
Periodic Solutions ◽  
Coupled Oscillators ◽  
Topological Structure ◽  
Seismic Isolation ◽  
Degrees Of Freedom ◽  
Linear Oscillator ◽  
Resonance Capture ◽  
Low Frequencies ◽  
Flutter Suppression

We study, numerically and analytically the dynamics of passive energy transfer from a damped linear oscillator to an essentially nonlinear end attachment. This transfer is caused either by fundamental or subharmonic resonance capture, and in some cases is initiated by nonlinear beat phenomena. It is shown that, due to the essential nonlinearity, the end attachment is capable of passively absorbing broadband energy both at high and low frequencies, acting, in essence, as a passive broadband boundary controller. Complicated transitions in the damped dynamics can be interpreted based on the topological structure and bifurcations of the periodic solutions of the underlying undamped system. Moreover, complex resonance capture cascades are numerically encountered when we increase the number of degrees of freedom of the system. The ungrounded, essentially nonlinear end attachment discussed in this work can find application in numerous practical settings, including vibration and shock isolation of structures, seismic isolation, flutter suppression and packaging.

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