15min:

DAVID S. PERRY, ANTHONY MILLER, Department of Chemistry, The University of Akron, Akron OH 44325-3601; B. AMYAY, A. FAYT AND M. HERMAN, Laboratoire de Chimie Quantique et Photophysique, Université libre de Bruxelles, B-1050 Brussels, Belgium.

The link between energy-resolved spectra and time-resolved dynamics is explored quantitatively for acetylene (¹²C₂H₂), X¹ _g⁺ with up to 8,600 cm^-1 of vibrational energy. This comparison is based on the extensive knowledge of the vibration-rotation energy levels and on the model Hamiltonian used to fit them to high precision.\footnoteB. Amyay, S. Robert, M. Herman, A. Fayt, B. Raghavendra, A. Moudens, J. Thiévin, B. Rowe, and R. Georges, J. Chem. Phys. \underline\textbf131, 114301 (2009). Simulated intensity borrowing features in high resolution absorption spectra and predicted survival probabilities for intramolecular vibrational redistribution (IVR) are first investigated for the ₄+ ₅ and ₃ bright states, for J = 2, 30 and 100. The dependence of the results on the rotational quantum number and on the choice of vibrational bright state reflects the interplay of three kinds of off-diagonal resonances: anharmonic, rotational l-type, and Coriolis. The dynamical quantities used to characterize the calculated time-dependent dynamics are the dilution factor _d, the IVR lifetime _IVR, and the recurrence time _rec. For the two bright states ₃+2 ₄ and 7 ₄, the collisionless dynamics for thermally averaged rotational distributions at T = 27, 270 and 500 K were calculated from the available spectroscopic data. For the 7 ₄ bright state, an apparent irreversible decay of is found. In all cases, the model Hamiltonian allows a detailed calculation of the energy flow among all of the coupled zeroth-order vibration-rotation states.