التفاصيل البيبلوغرافية
| العنوان: |
Dynamics and the breaking of a driven cage: I2 in solid Ar. |
| المؤلفون: |
Bihary, Z., Karavitis, M., Apkarian, V. A., Zadoyan, R. |
| المصدر: |
Journal of Chemical Physics; 4/22/2004, Vol. 120 Issue 16, p7576-7589, 14p, 2 Diagrams, 14 Graphs |
| مصطلحات موضوعية: |
WAVE packets, TRANSDUCERS, RESONANCE, MOLECULAR dynamics, GAUSSIAN processes, MULTIPHOTON processes, BALLISTICS, PHOTODISSOCIATION |
| مستخلص: |
Pump–probe measurements of I2 in solid Ar are reported and analyzed to extract a description of cage response to impulsive excitation, from the gentle kick, up to the breaking point. The most informative data are obtained through wavepacket motion on cage-bound, but otherwise dissociative, potentials where the chromophore acts as a transducer to drive the cage and to report on the local dynamics. This general class of dynamics is identified and analyzed as a function of energy in Ar, Kr, and Xe. The overdriven cage rebounds with a characteristic period of 1.2 ps that shows little dependence on excitation amplitude in all hosts. After rebound, the cage rings as a local resonant mode in Ar, with a period of 1 ps and dephasing time of 3 ps. This mode remains at the Debye edge in Kr and Xe, with periods of 630 and 800 fs, and dephasing times of 8 and 6 ps, respectively. In the bound B-state, the cage fluctuates toward its dilated equilibrium structure on a time scale of 3 ps, which is extracted from the down-chirp in the molecular vibrational frequency. When kicked with excess energy of 4 eV, the Ar cage breaks with 50% probability, and the molecule dissociates. The kinetics of polarization selective, multiphoton dissociation with Gaussian laser intensity profiles is delineated and the ballistics of cage breakout is described: The photodissociation proceeds by destruction of the local lattice, by creating interstitials and vacancies. During large amplitude motion on cage-bound potentials, sudden, nonadiabatic spin–flip transitions can be observed and quantified in space and time. The spin–flip occurs with unit probability in Ar when the I*–I bond is stretched beyond 6 Å. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
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