Light-induced opening of the fullerene C60 cage due to reaction with excited molecular oxygen (lo2) generated via C60 triplet energy transfer with 3 0 2 has been studied in thin films by differential IR spectroscopy, mass spectroscopy and q u a ntu m c hem ica I si mu lat io n .

The two-photon excitation spectrum in polycrystalline a-sexithienyl (7^) thin film has been investigated at 4.2 K in the spectral range between 910 and 1180 nm of the fundamental laser radiation. The intense two-photon absorption band at 18 350 cm -1 is assigned to the 2 l A g exciton band origin. The comparison of the one-photon and two-photon excitation spectra shows that the lowest "gerade" exciton level lies at 898 cm -l above the lowest one-photon-allowed 1 ] B U exciton level.

The microwave spectrum of (cyclopropylmethy1)acetylene (a newly prepared compound) was investigated in the frequency range 28-40 GHz. Both gauche and cis conformers were observed, the latter being 64 f 30 cm-' lower in energy. The geometries of these conformers were obtained combining the ab initio and microwave spectroscopy results. A large-amplitude motion (the methylacetylene group torsion) was studied by assigning the rotational spectra of several torsionally excited states.

No abstract

No abstract