ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The intramolecular dynamics of several model systems are investigated by using classical trajectories. Power spectra of auto- and cross-correlation functions obtained from the classical trajectories are used to classify the type of motion for excited local vibrational modes and to investigate the mechanisms of energy flow at various excitation energies. Coherency spectra are used to investigate interactions between two vibrational modes. Various models of four systems, HC3, HNNH, HCCH, and H2O2, are examined. The emphasis is on hydrogen peroxide. The motion is quasiperiodic at low energies of excitation. The onset of chaotic motion occurs at approximately 89% of the energy required for dissociation of the OH bond in H2O2. For acetylene the classical motion becomes chaotic only for energies very near the dissociation limit of the CH bond. For HC3 and HNNH, chaotic motion occurs at energies much less than that required for dissociation of the CH or NH bond. In general, the chaotic limit is lowered and the rate of energy flow is enhanced by the presence of bending degrees-of-freedom. The amount of energy transferred from a local mode is found to be invariant to the number of degrees-of-freedom in the chaotic regime while it is strongly dependent upon the number of degrees-of-freedom in the quasiperiodic regime. However, the initial rate of energy transfer in the chaotic regime is substantially affected by the number of degrees-of-freedom.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.452082
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