Quasi-Classical Trajectory Simulations of Intramolecular Vibrational Energy Redistribution in HONO2and DONO2†

2005 ◽  
Vol 109 (17) ◽  
pp. 8304-8309 ◽  
Author(s):  
Yong Liu ◽  
Lawrence L. Lohr ◽  
John R. Barker
Keyword(s):  
Vibrational Energy ◽  
Classical Trajectory ◽  
Energy Redistribution ◽  
Intramolecular Vibrational Energy Redistribution ◽  
Trajectory Simulations

State Preparation and Intramolecular Vibrational Energy Redistribution

1996 ◽  
Author(s):  
Tomas Baer ◽  
William L. Hase
Keyword(s):  
Vibrational Energy ◽  
Chemical Activation ◽  
Classical Trajectory ◽  
Unimolecular Reaction ◽  
Vibrationally Excited ◽  
Energy Redistribution ◽  
Rotational States ◽  
Intramolecular Vibrational Energy Redistribution ◽  
Singlet States ◽  
Reactant Molecule

The first step in a unimolecular reaction involves energizing the reactant molecule above its decomposition threshold. An accurate description of the ensuing unimolecular reaction requires an understanding of the state prepared by this energization process. In the first part of this chapter experimental procedures for energizing a reactant molecule are reviewed. This is followed by a description of the vibrational/rotational states prepared for both small and large molecules. For many experimental situations a superposition state is prepared, so that intramolecular vibrational energy redistribution (IVR) may occur (Parmenter, 1982). IVR is first discussed quantum mechanically from both time-dependent and time-independent perspectives. The chapter ends with a discussion of classical trajectory studies of IVR. A number of different experimental methods have been used to energize a unimolecular reactant. Energization can take place by transfer of energy in a bimolecular collision, as in . . . C2H6 + Ar → C2H6* + Ar . . . . . . (4.1) . . . Another method which involves molecular collisions is chemical activation. Here the excited unimolecular reactant is prepared by the potential energy released in a reactive collision such as . . . F + C2H4 → C2H4F* . . . . . . (4.2) . . . The excited C2H4F molecule can redissociate to the reactants F + C2H4 or form the new products H + C2H3F. Vibrationally excited molecules can also be prepared by absorption of electromagnetic radiation. A widely used method involves initial electronic excitation by absorption of one photon of visible or ultraviolet radiation. After this excitation, many molecules undergo rapid radiationless transitions (i.e., intersystem crossing or internal conversion) to the ground electronic state, which converts the energy of the absorbed photon into vibrational energy. Such an energization scheme is depicted in figure 4.1 for formaldehyde, where the complete excitation/decomposition mechanism is . . . H2CO(S0) + hν → H2CO(S1) → H2CO*(S0) → H2 + CO . . . . . . (4.3) . . . Here, S0 and S1 represent the ground and first excited singlet states.

Multiple timescales in the intramolecular vibrational energy redistribution of highly excited methanol

1995 ◽  
Vol 102 ◽  
pp. 167 ◽  
Author(s):  
Lucia Lubich ◽  
Oleg V. Boyarkin ◽  
Rebecca D. F. Settle ◽  
David S. Perry ◽  
Thomas R. Rizzo
Keyword(s):  
Vibrational Energy ◽  
Energy Redistribution ◽  
Multiple Timescales ◽  
Intramolecular Vibrational Energy Redistribution

scholarly journals Intramolecular vibrational energy redistribution and the quantum ergodicity transition: a phase space perspective

2020 ◽  
Vol 22 (20) ◽  
pp. 11139-11173 ◽  
Author(s):  
Sourav Karmakar ◽  
Srihari Keshavamurthy
Keyword(s):  
Phase Space ◽  
Energy Flow ◽  
Vibrational Energy ◽  
Energy Redistribution ◽  
Quantum Ergodicity ◽  
Connected Network ◽  
Intramolecular Vibrational Energy Redistribution ◽  
Vibrational Energy Flow ◽  
Classical Phase Space

The onset of facile intramolecular vibrational energy flow can be related to features in the connected network of anharmonic resonances in the classical phase space.

scholarly journals Direct observation of structural dynamics upon photo-excitation in a spin crossover crystal with femtosecond electron diffraction

2019 ◽  
Vol 205 ◽  
pp. 07005
Author(s):  
Yifeng Jiang ◽  
Lai Chung Liu ◽  
Henrike M. Müller-Werkmeister ◽  
Cheng Lu ◽  
Dongfang Zhang ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Structural Dynamics ◽  
Spin Crossover ◽  
Vibrational Energy ◽  
Intersystem Crossing ◽  
Structural Reorganization ◽  
Energy Redistribution ◽  
Intramolecular Vibrational Energy Redistribution ◽  
Femtosecond Electron Diffraction ◽  
Ligand Bond

Photoinduced spin transitions are studied by femtosecond electron diffraction to understand ultrafast structural dynamics associated with intersystem crossing. The results indicate the structural reorganization occurs within 2.3 ps, as the metal-ligand bond distribution narrows during intramolecular vibrational energy redistribution.

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