Pyrazine rotational states

For heavy molecules with very small rotational state spacing, this limit on AJ puts severe upper limits on the amount of energy that can be taken up in the rotations of a heavy molecule during a collision. Despite these limitations, P(E, E ) distributions have been obtained by inverting data of the type described here for values of AE in the range -1500 cm > AE > -8000 cnD for the two donor molecules pyrazine and hexafluorobenzene with carbon dioxide as a bath acceptor molecule [15,16]. Figure C3.3.11 shows these experimentally derived... 

Picosecond study of pyrazine seeded in supersonic 271 expansions of He. Decay behaviour interpreted in terms of rapid dephasing of initially populated singlet state Decays of rotational states of the (0-0) transition 310 of pyrazine. When Fourier transformed, beating decays are obtained... 

As we outlined in the theoretical section, the time dependence of the fluorescence is critically dependent on the type of exciting source used. We therefore list the experiments as a function of increasing laser width. We will first limit ourselves to the photodynamics of the J = 0, K = 0 rotational state of the lB3u of pyrazine, since only of that state we know the ME spectrum. 

Mullin A S, Park J, Chou J Z, Flynn G W and Weston R E Jr 1993 Some rotations like it hot seleotive energy partitioning in the state resolved dynamios of oollisions between COj and highly vibrationally exoited pyrazine Chem. Phys. 175 53-70... 

As discussed in Section III, TRPAD measurements are sensitive to molecular rotational motion by virtue of their geometric dependence on the molecular axis distribution in the LF. An elegant experimental demonstration of this has been performed by Suzuki and co-workers who measured the PAD temporal evolution from excited-state pyrazine [59]. In these experiments, the origin of the Si electronic state of pyrazine was excited by a pump pulse at 323 nm, and... 

Our calculations show that these second order terms are important for a quantitative description of nonadiabatic systems. This is demonstrated in the pyrazine S1/S2 system, where a reduced 4-mode model provides a qualitative picture with the main peaks of the spectrum in the correct places. The addition of second order terms and all degrees of freedom, results in the correct spectral envelope also being produced by the model. Also in the allene A/B system, the second order terms are required, not only for the correct description of the Duschinsky rotation in the excited state, but also for the high spectral density between the two bands. Even in the butatriene X/A system, in which second order terms play a minor role in the description of the spectral band, the inclusion of these terms means that the ab initio data could be taken with minimal adjustment, whereas a reduced dimensionality model required significant adjustment of the expansion parameters. 

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