ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Photodissociation cross sections have been calculated using a collisional time-correlation function (TCF) approach to light–molecule interactions. The method is based on separating the total TCF into the molecular dipole TCF of the target and the electric-field TCF of the light source. A norm-conserving time-dependent self-consistent-field approximation is implemented for the molecular dipole TCF of the target, which factors into a primary-region TCF, a secondary-region TCF, and a time-dependent phase factor. We present an application to the photodissociation of CH3I from vibrationally excited initial states with up to three quanta in the C–I and CH3 umbrella modes. The dynamics of energy transfer between the primary and the secondary region and its effect on the line shape functions for each initial vibrational state are systematically studied. The evolution of the primary- and secondary-region amplitudes is considered first for the initially excited (1,0) and (0,1) states of CH3I and shows the contrast between the fast oscillations of the primary-region amplitude and the slow oscillations of the secondary-region amplitude. A detailed study of the photodissociation dynamics of CH3I from the other vibrationally excited initial states is presented next. We fixed the number of vibrational quanta in the secondary-region dynamics, and studied the effect of increasing the vibrational excitation energy in the primary-region dynamics. Some of the vibrational energy given to the primary-region dynamics is transferred to the secondary-region dynamics. The reverse situation, vibrational energy transfer from the secondary to the primary region, is also obtained by fixing the vibrational quantum states in the primary-region dynamics and varying the excitation energy in the secondary region.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.461439
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